surfaces in a notorious double murder. a red flag at the top of the world. the mercury's rising, the ice disappearing. >> it's completely unprecedented. >> pelley: and steve hartman with a stock tip-- beware of singing to it. who's going next in the red trailer captioning sponsored by cbs this is the "cbs evening news" with scott pelley. >> pelley: today, donald trump retreated from his pledge to torture terrorists and kill their families. both would be illegal until the laws of war. in a statement, trump said that as commander in chief, he would not order u.s. troops to commit crimes. but it was just last night in the 11th republican debate that trump boasted the military would not refuse his orders. that debate sank deeply into pointless insults.

it with words including "embarrassing, suicide, and implosion." it left many republicans feeling they were banging on the cockpit door of a party that had been hijacked with no idea where the g.o.p. was headed or whether it would land in one piece. here's major garrett. >> millions and millions of people are coming to vote for the republicans, and joining the republican party because of me. >> reporter: donald trump today sought to take control of the republican party just hours after clashing with his rivals at the 11th g.o.p. debate. >> this little guy has lied so much-- >> here we go. >> about my record. >> here we go with the personal stuff. >> he has lied so much. >> reporter: the rift between trump and the republican establishment continues to grow. trump canceled his saturday appearance before an annual conference of conservative activists, drawing ridicule from ted cruz. >> he was told there were conservatives that were going to be here.

conservatives were skeptical of trump. >> if he doesn't show up, i think he's kind of dodging what's going on here. >> i don't think he represents our values at all. >> donald trump is a phony, a fraud. >> reporter: as mitt romney and other g.o.p. leaders plot ways to deny trump the nomination, republican national committee chairms reince priebus said the turmoil would not hurt the party's chances in the fall. mr. chairman, is your party coming apart at the jeems not at all. i think what we're seeing is drawm and intrigue. >> reporter: what is the probability of an open or contested jeengz you know, i don't know about that. i still believe it's likely we wouldn't go to a contested convention, but whatever the case is, we're going to be prepared. >> please, i know it's hard to interrupt. >> that's not what you said in the op-ed. >> breathe, breathe, breathe. >> reporter: despite the rancor at last night's debate, all the candidates pledged to support eventual republican nominee. >> because i gave my word that i would. >> reporter: at the

skipping ben carson today formally ippedded his campaign. carson offered no endorsement but said he left behind being boisterous and loud in high school. >> pelley: major garrett, thanks very much. the next contest for the democrats are tomorrow in kansas, louisiana, and nebraska, michigan on tuesday. here's nancy cordes. >> there were so many insults flying back and forth, it was hard to keep track. >> reporter: in detroit, the republican debate drew a brief mention from clinton, but she quickly turned to michigan's economy, taking a tough line on trade in a state hard hit by outsourcing. >> and we don't take action until after the damage is done, which often means after workers are laid off. that is ridiculous. >> reporter: in traverse city, bernie sanders argued he, not clinton, has consistently opposed free trade deals. >> nafta and permanent normal train relations with china have cost this country millions of decent-paying jobs.

candidates, winning michigan is about more than just delegates. they have both visited water-stricken flint, and both want to show, scott, that they are the ones who are equipped to solve crises like that one when they arise. >> pelley: nancy cordes, thanks. in another important story tonight, the cease-fire in syria appears to be holding, and that gave our elizabeth palmer a chance to explore aleppo, syria's largest city, with two million people before the five-year-old civil war. >> reporter: for three years, in the heart of aleppo, rebels battled syrian soldiers, and by the time the army had won, the world had lost one of its greatest cultural jewels, the city's ancient market. there are some things that people on both sides of this very bitter conflict have in common. one is the destruction, terrible here in the government-controlled area, and down there, with the opposition holds ground, it's just as bad.

exhaustion and misery. you see that on every side in salahuddin, a poor neighborhood right on the front line, where tarps shield residents from the eyes of snipers and families eke out life in the are ruins. can we come up and see you? the ganzi family invited us inside. there's no running water or electricity. in their tiny apartment, she explains her son, a soldier, was killed in action. without his salary, everyone, including the five grandchildren, is surviving on charity. game. crutches now. it's been a year since a rocket took off his leg. were you coming back from school? "no," he says. "i was doing errands with my mom." people can still do errand and shop for food in the part of

to bits, and since the cease-fire, the mood has lightened. back in the old city, major ghanem, the officer in charge, tells me things are quiet here, too. the soldiers are relaxed, stocking up on supplies in spite of the odd rebel potshot. but what's next? how do you think this will end? "i am hoping for negotiations," he tells me. "we've already spilled too much blood." everyone we spoke to, scott, battered and ground down by this terrible war, is hoping for peace through negotiation, butt very same time, the syrian army is tightening a siege on the opposition-held side of aleppo so things could get a lot worse before they get any better. >> pelley: elizabeth palmer with remarkable, rare reporting from inside syria. thanks, liz. our next story got the attention of the entire country today. even the president mentioned it.

today that a knife is being tested to see if it's connectedly to the 1994 double murder for which o.j. simpson was acquitted. here's ben tracy. >> reporter: the knife given to los angeles police was allegedly found nearly two decades ago by a construction worker during the demolition of o.j. simpson's brentwood estate. the worker reportedly gave it to a policeman. neiman: >> the person we received this knife from is a retired l.a.p.d. officer who retired back in the late 90s. >> reporter: that former officer has not been publicly identified, but he's believed to have had the knife for many years before turning it in about a month ago. marcia clark prosecuted o.j. simpson for the stabbing deaths of nicole brown simpson and ron goldman. clark spoke to entertainment tonight. >> if it does turn out to be connected to the murders of ron and nicole, it would be interesting if there were some

pointed to who might have helped to bury it if, indeed, someone else did. >> reporter: the knife used in the murders has never been found. during his trial, simpson famously tried on a bloody glove discovered at his house. that evidence was dismissed by his attorney, johnnie cochran. >> if it doesn't fit, you must acquit." >> reporter: the l.a.p.d. says the story behind this new knife could turn out to be bogus. >> do you know what's going on here! o.j.'s in the back seat with a gun to his head! >> reporter: it comes as a cable miniseries recounting the in the case. >> it's remarkable. i mean, this is the case that never ends. >> reporter: law professor laurie levenson covered the simpson trial and says the knife is a fascinating development but of little legal significance. >> even if they find some evidence on this, they would have to show chain of custody. they would have to show how it got there, and even if they said, "it was o.j.'s and

for the murder. there's double jeopardy. >> reporter, of course, o.j. simpson is already behind bars. he is serving a prison sentence in nevada on an unrelated case. as for this newly found knife, scott, the l.a.p.d. said they are not sure when they will get the test results on that knife. >> pelley: ben, thanks. there was a long-awaited groundbreaking today in flint, michigan. a crew dug up a corroded lead pipe outside a home where an expectant mother and eight-year-old girl live and replaced it with a copper pipe. one down, about 8,000 to go. here's adriana diaz. >> i'm toni. i'm one of the nurses from the health department. >> reporter: nurse toni larocco was checking on stephanie bradley's one-year-old daughter who tested positive for lead in september. >> has she been retested? >> she was retested and it was >> reporter: this is one of five house calls they will make

lead poisoning. how has the load of homes you have to visit increased? >> it's gone up huge, and the numbers of families we've seen have exponentially grown. >> reporter: stephanie bradley said she drank the contaminated water throughout her pregnancy. when you were first told your daughter had high levels of mind? >> well, i was very, very afraid because of how young jung she is, and i didn't know the dangers of it. >> reporter: five months after flint switched its water supply back to lake huron, nearly 1,000 homes still have dangerous levels of lead in the water and 72 children are still testing positive for high lead levels in their blood. but only half of flint's 8,000 children under six have been screened because testing is voluntary. since lead can remain in the body for decades, the state is developing a registry to track flint residents for years. but stephanie says until all the lead lines are out, she'll be afraid of how the water is

>> it's making me want to leave the city of flint, to move just because of the water and everything. it's-- it's-- it's frustrating. >> reporter: the city says right now there's only enough funding to replace 30 lead pipes out of 8,000. flint's recovery will likely be a recurring theme in sunday's democratic debate. scott, it's being held right here in flint. >> pelley: adriana diaz in flint for us tonight. adriana, thank you. now, to the economy. hiring surged last month as employers added 242,000 jobs. the unemployment rate held steady at 4.9%. that is an eight-year low. the latest thing in cars is the stretch loan, to pay for them. a new report out today finds that the average loan runs more than five years now, 67 months for a new car, 63 months for a used car.

$29,551. mellody hobson is our cbs news financial analyst. why are people taking out these long-term loans? >> during the great recession people stopped buying carses. then what happened, five, six years went by, and car prices outpaced inflation. so in order to be able to afford that $30,000 car, people have longer periods. >> pelley: what's the downside? >> huge downside. the longer the payment, the more you're going to pay in interest. think about it. a car loan used to be four years. today, the average loan being 67 months, some as long as 72 months, seven years, means that when you tack on that extra period the average person is spending about $8,000 more in interest. >> pelley: and so do you think consumers should be taking these loans or avoiding them? >> avoiding them. i'm absolutely against them, not

is really expensive, but also the ideal that you could get into a situation later in the loan years where your car is like a house-- under water-- meaning the car is worth less than the payments that you're making. that's not a good deal. >> pelley: that got us into a lot of trouble before. mellody hobson, our cbs news much. >> thank you. >> pelley: scientists can't is melting. and would you believe anchorage

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this winter, enough ice is missing to cover california three times. here's don dahler. >> reporter: the arctic ocean is six million square miles, most of it covered in ice. but last month, the top of the world was up to 14 degrees above normal and broke the record for the lowest amount of ice in february, more than 400,000 square miles short. >> it's completely unprecedented. people who work up there, you know, go up to the arctic, go out on boats and cruise around to measure these things are absolutely stunned. >> reporter: robert newton is an arctic researcher at columbia university. >> it's the dead of winter there. there's no light. it's well below freezing. it should be locked in with ice all the way across, but the ice is significantly retreated, even in wintertime. >> reporter: the shrinking sea ice could have a potentially disastrous effect on animals, such as polar bears and seals, who depend on the ice to hunt

ice-free oceans absorb more heat and become warmer, which speeds up glacial melting, raises sea levels even more. >> ice is a great reflector of light, which is where most of the heat on the planet comes from. open water is dark. it's a fantastic absorbedder. >> reporter: newton says changes in the arctic can also affect weather here, causing storms and droughts to last longer and be more extreme. fascinating for scientists, but scary for a person? >> scientists are both scientists and people, so we are both fascinated and frightened by it, yes. >> reporter: the fear is that changes happening now in the arctic might be irreversible. newton says the recent climate change agreement signed by 195 nations was a start, but, scott, that it doesn't go far enough to reverse the trend. >> pelley: don, thanks.

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>> pelley: about 100,000 students are sharpening their number 2 pencils for the new s.a.t. college entrance exam tomorrow. it's a complete overhaul. the essay is now optional, questions have four answer choices, not five. there's no penalty for incorrect answers. and ridiculous vocabulary words like abstemious are gone, replaced by words students actually use like synthesis. abstemious, by the way, means austere, and there was nothing abstemious about bud collins. for 50 years, the colorful chronicler of tennis in newspapers and on tv. collins was easy to spot with his bow tie, wild shirts and pants, even at wimbeldon. but collins suffered from dementia. he died today at 86. in the west, el nino rains that fizzled in february are expected to storm back in buckets

nearly a foot in some places could put a dent in california's drought. the sierra nevada is in for high winds and heavy snow. meanwhile, back at the ranch, it's animals, vegetables, and miracles. steve hartman next. feel secure in your dentures... feel free to be yourself all day. just switch from denture paste to sea-bond denture adhesive seals. holds stronger than the leading paste all day... without the ooze. feel secure. be yourself.

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muscle or nerve conditions, medications including botulinum toxins, antiplatelets and blood thinners, may increase the risk of serious side effects. ask a urology specialist >> pelley: we end tonight with a catalytic conversion. road. >> come on! >> reporter: all cattlemen face challenges beyond their control but not long ago at this ranch south of houston son clarence thomasy sonnen faced a problem of his own, i doing. >> you know, every marriage has the issues.

>> i was as unprepared for it as anybody. what's that? >> reporter: it all began innocently enough. >> want to come lay down? >> reporter: shortly after they got married six years ago, renne started hanging out with the livestock. tome warned her. >> "renne, don't name those cows." listen. then she started singing to them, too who's going next in the red trailer >> reporter: and before long, this rancher's wife had turned into a rancher's worst nightmare, a vegan, who couldn't stomach so much as living on a cattle ranch anymore. >> he was just going to get out of business and our marriage was going to be over. >> it wasn't working and i said, "i'm going to sell the whole herd." and she said, "if you're going to sell the whole herd anyway, why don't you sell them to me." >> and he looked at me like, you have lost it. you are crazy. >> reporter: clearly there was some truth to that.

that renne had been secretly posting a blog called vegan journal of a rancher's wife. she attracted thousands of followers, and through those contacts, renne was able to raise $30,000, enough for a hostile takeover. >> all of a sudden he was wife. >> reporter: is this not emasculating in any way? >> no! >> yeah. i didn't appreciate it, but, you know, it was growing pains. this story gets good. after his wife raised the money, tommy did something rare for a rancher or any man, for that matter-- he put aside his ego and reconsidered a core belief. >> how you doing, girl? >> reporter: he stopped eat eating meat, liked how it felt, and now works for his wife at the rowdy girl vegan farm animal sanctuary. as best we can tell, the only cattle ranch conversion in the country. so now that he's change forward you, how would you like to

>> i can't think of a thing. >> ah! >> reporter: and there is everything you need to know to stay married forever. steve hartman, "on the road,"" in engelton, texas. >> pelley: and that's the cbs evening news for tonight. for all of us at cbs news all around the world, good night. captioning sponsored by cbs captioned by

access.wgbh.org 20 years after the o.j. simpson trial. >> police made a shocking discovery. >> was the knife used in the double homicide found in the rubble of o.j. simpson's mansion? then, donald trump movie

>> is a new sacha baron cohen movie being suppressed because it insults trump? >> as trump defends his man has had. >> you were making reference to your private parts and people were saying it wasn't very presidential. >> and donald trump and megyn kelly. what the body language experts say. and sheryl underwood. her troubled life. >> have people been stunned by your revelation? >> the private tears of a tv host. you can eat what? barbecue ribs, chicken parm. even brownies. how you can eat it all and still lose weight. >> perfect. now, "inside edition" with deborah norville. >> deborah: hello, everybody, and thank you for joining us. has the knife from the o.j. simpson case finally been found more than 21 years after the double murders?