tonight on "nightline," the kennedy curse? news tonight of yet another tragedy for the famous kennedy clan. as mary kennedy is found dead of an apparent suicide. another painful turn in a family of political glory. and high stakes horses. an investigation into what really happens behind the scenes in the lucrative world of walking horses, the shocking, undercover video that shows how many of these beautiful beasts get their elegant trots. plus the fame. today the forbes celebrity 100 crown j.lo the most powerful

star on the planet, muscling out oprah, bieber, and gaga, from clothing lines to twitter followers, what it takes to be number one. good evening, i'm cynthia mcfadden. tonight another chapter in the long ark of the kennedy family story. when mary richardson kennedy, the estranged wife of robert f. kennedy jr was found dead of an apparent suicide in her home. the unexpected death of yet another member of the storied clan brings to mind their long history of very public sorrows. a political family of immense wealth, and incredible power, that's suffered terrible loss time and time again. >> reporter: it is a family

marked by greatness and tragedy, the kennedys of boston. wealthy and powerful, so glamourous that when they put a son in the white house, it was called camelot. but for all their accomplishments, you cannot say the name kennedy without a pause. once again, this family to whom so much has been given, has had so much taken away. today the latest sadness, this afternoon police in bedford, new york, said they responded to calls about a possible unattended death and found the body of mary richardson kennedy, 52 years old. source rs tell abc news, she hanged herself. mary was robert f. kennedy's jr's estranged second wife. together they had four children. robert kennedy had this to share with them, he know what is it is to mourn the loss of a parent. his father, his brother's

closest confident was assassinated as he campaigned for president back in 1968. the family's losses started much earlier of course. jos ep kennedy jr, the oldest brother, who was expected to rise to prominence, i was killed in 1944 during world war ii when his explain cloded. four years later, his sister died in a plane crash in france. no loss of greater than that of the president. the entire nation seemed to mourn the president back in 1963 when he was felled by an assassin bullet in dallas. who will ever forget this picture of his son john saluting? just recently this tape emerged of the 3-year-old john talking about family historian arthur schlesinger. >> john, what happened to your father? >> um, he's gone to heaven. >> reporter: that boy, who the

nation called john-john, of course grew into a dashing man. who himself died tragedically in 1999 behind the wheel of a piper plane he was piloting at the age of just 38 off the family's beloved cape cod. his wife died too that night, and her sister. once again the kennedy clan gathered together to mourn, led by john's uncle. it reminded us again of the whispered phrase, the kennedy curse. >> well, i don't sub skrub to the curse thery. i think the common thread is life in the 20th century is risky. we tend to see people of immense wealth as people who are somehow removed from the dangers, risks, pitfalls of life and of course that's fantasy. they seem to be the family that has everything, but they don't. one of the things they don't have is control over their own

destinies anymore than anybody else does. >> three years ago, the death of ted kennedy reminded us of how the last surviving brother had fallen from grace when he drove a car off a bridge, killing a young woman in 1969. his quest over the last 30 years to live up to a failing ideal. the sons and daughters of those brothers have suffered too, born into what has been called america's royal family. patrick kennedy, the son of ted, spoke to abc's christiane amanpour about his own struggles with addiction, after he crashed his car while a u.s. congressman. >> i don't recall much about the night. i do know that i was under the spell of addiction. and when you're under the spell of addiction, you're just an accident waiting to happen. >> reporter: many in patrick's generation have worked valiantly to carry on their parents' legacy of public service.

robert kennedy jr among them. he's a passionate and ut spoken environmentalist who has fought legal battles on behalf of a dozen franchises. after 16 years of marriage, he and his wife had separated. she had struggled mightily with alcohol abuse over the past several years. tonight multiple sources say she was found by a maid in the garage of her home in new york, apparently having hanged herself. mary richardson kennedy leaves behind four children ages 11 to 17. the richardson family has said in a statement, that, quote, our beloved sister will be sorely missed and our hearts go out to her children who she loved without reservation. up next, their stride made them beautiful champions, but at a steep cost. we investigate the world of these prized horses. sarah... will you marry me?

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tonight we investigate a high-stakes horse competition, where the winner can stand to rake in millions. the alarming story of a breed of horses treasured for their prize-winning prance, being abused on hidden camera by a handler wanting to improve their fancy foot work. at a terribly painful price. here's abc's brian ross with tonight's "nightline" investigates. >> tennessee walking horses are known to be gentle and sweet, which makes what you are about to see, all that much more outrageous. a powerful video that documents just how far some will go to win ribbons and medals at prestigious horse shows.

a warning, for some this video will be disturbing to watch, but without seeing it, it would be hard to believe such crueltyy would be possible. >> kentucky has its derby, but tennessee has its famed walking horses. with their high-stepping gait, originally trained so plantation members would have a smooth ride. but now lots of money is at stake. with millions of dollars in stud fees for a winning horse at the annual celebration. the competition is fierce and for years there's been great suspicion in the horse world about how some top trainers get their horses to produce. >> it's a stride, it's a gait. not something that any morse does naturally. it's a totally artificially man-made gait. now there's proof of what some trainers are doing behind the scenes. tennessee' beautiful horse country, down this gravel road,

caught on tape in this farm, undercover video being seen for the first time tonight, made by an investigator for the humane society who went to work for one of the american leaders in the sport. jackie mccut seen here beating a horse. keith of the humane society described what is known as soring. >> they'll apply drops of mustard oil, diesel fuel, hand cleaners that have a caustic effect to them. >> right on the horse's -- >> right on the ankle. then they'll wrap it with a plastic wrap. that will cause the chemicals to seep into the skin of the horse, making it very tender. >> then later, the video shoz mcconnell putting heavy metal chains around the open store. then when the horse is ridden, the horse hits that chain and

causing that reaction. >> so it's a flinch? >> essentially, yes, the horse is responding in pain and picking up their feet. >> the horses on the video appear in such great pain, they often refuse to get up and are whipped by the stable hands. in other scenes, mcconnell and his stable hands use sticks and prods in what the humane society says is stewarding. teaching the horse to stay still while they test for sensitivity to pain. >> one trainer will burn the horse with cigarettes at the training barn. >> the trainer caught on this tape is well known in the walking horse world. hired again and again by wealthy patrons to train their horses. when this video was recorded last year, mcconnell was on a federal disqualification list but continued to train horses and show up at events where he boasted of what he was doing. >> it's looking pretty good.

>> reporter: mcconnell is not so cocky now, facing a federal indictment based on the undercover tape. >> do you have any regrets about what you did? >> i have no comment. >> he showed no signs of remorse when he tracked him down this week. >> don't you want to say something about that? don't you want to apologize? don't you want to apologize? >> do people have to cheat to win? >> no, sir. >> their steve mullins runs an organization formed three years ago to test tennessee walking horses at major events and stop the abuse. take a look at this. we showed him the undercover tape of mcconnell. >> i think it's disgusting. i don't condone that at all. >> reporter: is this widespread? do other trainers do the same thing and do if for years? >> i can't speak about years before, but i do not believe that goes on now. i do not believe that's rampant. >> reporter: but at last year's

celebration, in a random inspection, 52 horses out of 52 horses had foreign sub stances on their skin when tested. jenny jackson has been a walking horse trainer for 40 years and says it remains a widespread problem. she and her husband nathaniel have been trying to clean up the mess. she says she was part of it when she first started. >> i couldn't believe how vicious i had become. the cruelty, the monster that i had turned into, to make those horses do that. and it just rips my heart apart, because i know what they're going through. for a blue ribbon that costs $1.95. >> reporter: we went back to mcconnell stable this is week and found it pretty much out of business. all of the stalls empty, except for this one, but for the humane society video, it would be hard

to believe that anyone could treat an animal like this, the way mcconnell did for so long until he was finally caught. jackie mcconnell's lawyer says he'll go to court next week to plead guilty to one of the counts on which he was indicted. late today we heard from one of the sponsors of the walking horse championship, pepsi, which says it's severed its ties with the event as a result of our abc news investigation. >> so important. thank you, brian. up next, j.lo is this year's hottest star in the world according to forbes magazine. how she beat out beeber and beyonce, and oprah. literally across the street from her sister. [ banker ] but someone else bought it before they could get their offer together. we really missed a great opportunity -- dodged a bullet there. [ banker ] so we talked to them about the wells fargo priority buyer preapproval. it lets people know that you are a serious buyer

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this year jennifer lopez danced, sang, tweeted and judged her way to the top of the forbes sebl 100 list, leaving steven spielberg, katy perry, and last year's winner, lady gaga, in her dust. so just how did she beat them all to become the biggest power player? here's abc's t.j. winick. ♪ >> reporter: last year the forbes celebrity 100 was topped by lady gaga. the most unusual performer in pop music. her new album, born this way, sold a million copies this first week. with the entertainer pulling an impressive $90 million in 2011. but it turns out 2012 isn't as

goo goo for ga ga, the new number one on the block is jenny from the block. ♪ >> reporter: because the forbes list is not just about money. it's about everything that makes someone famous these day, social media, tv endorsements and internet traffic. j. lompt is on top with six million followers on twitter and 12 million fans on facebook. >> it's amazing. you attack every single song. >> reporter: she's on tv all the time, judging on american idol. business wise, her split from marc anthony gave birth to a new identity, opportunities with l'oreal and gillette. ♪ >> reporter: at the same time, a steamy music video called, i'm into you, j. lo kaf orting on the beach with a man 11 years younger, only makes her hotter.

♪ >> reporter: then there's her clothing line with kohl's. >> it's not enough for a celebrity to sing really well. your celebrity has to be extended into a clothing line, like with what j.lo has, not just singing, but being on tv and movies. it's a critical part of being a celebrity today and she really has all of that going on. >> reporter: in second place, 2010's number one, oprah winfrey, her iconic talk show may have ended and there might be that struggling cable network, but before you shed a tear, she's still the number one earner on the list with $165 million thanks to her empire of spin-off shows, her magazines, and her satellite radio deal. number three is the youngest on the forbes list. ♪ >> reporter: oh, baby, you guessed it, 18-year-old heartthrob justin bieber. not only did the canadian crooner earn $55 million this year, but forbes calls him a

budding venture capitalisting using his dow to invest in several start-ups. >> he's doing more than just singing and building that career. he's building this other career on the side and that one has the potential to last way beyond the time that he's famous. >> reporter: if targeting a younger audience is good as gold, then it's no surprise this year, two of the three kardashians made the cut. say what you will, kris jenner's girls know how to stay relevant and earn millions doing it. and that infamous wedding, it was quite the money-maker, as was the publicity from the divorce just a few months later. that's why kim ranks seven on the forbes list with $18 million, ahead of tom cruise, brad, even angelina. >> these guys know how to work fame and make money from it. they're brilliant at it. even if you hate them, you're still watching them. that's why they're on our list. >> being famous for just being