this is "nightline." >> tonight, america in black and white. the right to bear arms out in the open. >> it just feels unnecessary to me. >> meet the open carry texas movement, toting military-style rifles in public. and at the deadly protest in dallas, people with rifles strapped to their backs confusing policeamidst the chaos. we go inside the controversial pro-gun movement. plus imagine someone who's a spitting image of you but you're not a twin. and that identical face belongs to a complete stranger. the doppelganger detective scouring the globe to bring them together. making it official. bernie sanders endorsing hillary clinton. but as they come together to fight a common enemy, how

are they really? >> hello new hampshire! >> but first the "nightline 5." >> tired of redosing antacids? try duo fusion. new two in one heartburn relief. the antacid goes to work in seconds. the acid reducer lasts up to 12 hours. in one chewable tablet. try duo fusion from the makers of zantac. your heart loves omega 3s. the omega 3s in fish oil differ from mega red krill oil which is easily soeshed by your body. the difference is easy to

good evening. the president spent the day in dallas, comforting the nation after the deadly police ambush there.

chaotic in the moment for law enforcement by the presence of armed protesters. texas is home to the controversial open carry texas movement whose members walk around in public with their guns on full display. my "nightline" coanchor byron pitts goes inside the group for our week-long series "america in black and white." ♪ ♪ glory glory hallelujah >> reporter: today the city of dallas taking time to mourn. gathering to remember the lives of five officers killed in last week's horrific attack. putting politics aside, president obama and the first lady, hand if hand with former president george w. bush and first lady laura bush. the president delivering a sermon of sorts. >> i'm here to insist we are not as divided as we seem. and i know that because i know america. i know how far we've come against impossible odds. >> reporter: his poignant

observation that in the audience, mourning of all sides. >> i see people who mourn for the five officers we lost, also weep for the families of alton sterling and fill lawn dough castille. i see what's possible when we recognize we are one american family. >> reporter: thousands having paid their respects over the last few days. these squad cars outside dallas police headquarters. a mill shift memorial filled with messages of hope and loved. the 11 injured and the families of those killed in the line of duty. >> this is very humbling. >> reporter: drawing visitors from all walks like first sergeant c.j. grissom, gun advocate and founder of open carry texas. he came to dallas to pay his respects. >> it's good to see that we can still come together when we recognize that what happened should not have happened, regardless. >> reporter: his group an eclectic mix of gun enthusiasts who pack heat in public. >> my ability to carry a rifle in self-defense should never be infringed upon.

a ak-15, a derringer, it doesn't matter, the second amendment is a self-defense tool. >> reporter: in a city still on edge the sight of exposed guns causing fear and concern. >> it feels unnecessary to me. like concealed i understand. but that is just excessive. i don't understand the point. >> reporter: texas is an open carry state. and walking around like this is legal. in the last few days their actions have drawn criticism. >> they will make an issue out of it, flip you off. >> reporter: here at last week's black lives matter rally, 20 to 30 men were seen with rifles strapped to their backs, wearing gas masks and bullet-proof vests quhr shots were fired, confusion. about who was responsible and how many shooters. this man carrying an ar-15 identified as a suspect. the dallas pd tweeting, this is one of our suspects, please help us find him. mark hughes turn himself in to police. he was

released. immediately i flagged down a police officer. >> he was allowing himself to carry an arm, a firearm, but that's his constitutional right. >> reporter: dallas police chief david brown said open carry laws blurred the line between potential suspects and the marchers. >> when people have ar-15s slung over and shootings occur and crime and they begin running, we don't know if they're a shooter or not. >> it's easy to tell who the bad guy and the good guy is. the good guy has his rifle on his back, not pointed at you firing. >> reporter: christian as 20-year army veteran and father of three. >> in combat i had no problem discerning who was the enemy, and everybody had guns. all it takes is a little bit of analysis and good training. >> reporter: he may be critical of police but he's not quick to support movements like black lives matter. >> what's wrong with the black lives matter movement is that we're minimizing the other people who are being killed by police officers unjustifiably. >> reporter: grisham says like

alton sterling and philando castil castille, he's been there, under an officer's gun, fearing for his life. he says this traumatic event in 2013, caught on police patrol dash cam, was the spark that ignited open carry texas. >> i was arrested. my son and i were going on a hike -- >> reporter: grisham said he brought that rifle strapped across his chest to protect them from wild animals. halfway through our hike a police officer approached. >> some reason why you have this? >> because i can. >> reporter: since carrying a rifle is legal, even without a license, christian believes what happened next was illegal. >> hey, don't -- >> at that point he pulled his gun, stuck to it hi head, threw me into the car. >> reporter: his son chris videotaped the arrest also. the father charged with interfering with a police officer and taken to jail. >> i'm going to do everything you say. >> my son had to watch this whole thing. >>

grisham two years ago he told us he was still battling the demons from tours in iraq and afghanistan. the arrest, his first time in jail, he said, triggered one of the worst episodes of ptsd he's ever endured. >> i've always been a gun rights advocate. but this turned me into an activist. >> how long are you keeping me in jail for? >> reporter: grisham walked away with a mission, a movement born. a goal to expand open carry right in the state of texas. at the time it was only legal to openly carry so-called long guns like ar-15s. state law prohibited the open carry of handguns. but just last year the law passed, giving texans with a permit the right to open carry handguns. while fighting for those gun rights in 2014, grisham invited me along to a rally in san antonio. >> there are folk in the country you are scaring. >> i realize there are people that have what i call an an irrational fear of guns. >> reporter: he stresse

fact that he always calls ahead to alert police about their marches. we met nearly two dozen well-armed supporters from retirees, children, men and women, gun lovers of every race. >> so often when these events are covered by the media, i may see this gentleman, i may see that gentleman, but i don't see you there. >> my house was robbed by five guys about four months ago. the police did nothing. so therefore i think it's my duty to protect my family. >> reporter: open carry members passing out fliers in one of san antonio's busiest intersections. most motorists are supportive. but some -- >> what do you think of these guys? >> [ bleep ]! what do you think? >> i'm a journalist, i'm getting opinions. >> run away! >> even if you took all guns away, if guns had never been invented, people still commit evil against other people. there's more people killed by hammers and clubs and fists than by firearms. >> actually, the latest fbi data shows

for 68% of homicides in this country. clubs and fists, 9%. but america's gun debate is far more than statistics. it's emotion. it's culture. horrific headlines, mass murders that can easily be explained away. from dallas to orlando. and in baton rouge. last week i encountered another open carry advocate outside the triple s mart where alton sterling was shot and killed by police. tell me the weapons you have with you and why. >> here a sub compact glock 4. this is ar-15 pistol. >> why is it necessary to walk around? >> it's not necessary. one of the reasons i do it is education. a lot of our youth feel they may protect themselves. in a lot of cases they may get weapons that come off the street or something like that. not knowing that they can have a weapon that's legal. >> reporter: gun control advocates and some political leaders strongly disagree, saying more guns is not the solution. >> we

many guns that it is easier for a teenager to buy a glock than get his hands on a computer or even a book. >> reporter: and with the republican convention ahead in ohio, a state with no open carry regulations, tensions are high. some worry about visitors and protesters bringing firearms to the city. for "nightline," i'm byron pitts in dallas. up next, which one is the real kim kardashian? and that's not bradley cooper. the bizarre doppelganger phenomenon. how to find your look-alike. ♪ take on any road with intuitive all-wheel drive. the nissan rogue, murano and pathfinder.

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know someone who could be your identicatwin. well, you might just have a doppelganger, a perfect strange history could pass for a twin separated at birth. here's another look at a way to help you find out with a few clicks of the mouse. >> are you two twins? >> reporter: meet maddy and amber. the pair look like twins. but believe it or not, they're complete strangers. >> no, we're not even related. >> no, you're kidding me. >> reporter: they're doppelgangers, a mysterious phenomenon in which two people look nearly identical. sometimes they're entirely unrelated. who can forget these bearded redheads who found each other on the same plane? even celebrities. adam sandler met his done bell banger on the red par pet, inviting him to the premiere of "the do-over."

with a selfie with her doppelganger. it isn't all glitz and glam more. mario looks so much like shia labeouf, he was punched in the face. folklore has it we each have seven look-alikes in the world. this dublin native is looking to prove that theory. these already met three of her own doppelgangers. >> oh my gosh, this is crazy. >> reporter: he very first meet-up went viral and has been viewed more than 8 million times. since then, niamh's been a doppelganger detective of sorts. cofounding the website twinstrangers.com. to help others in their search. >> i think people want to find their twin strangers out of curiosity. it's not a burning desire to find someone who looks like you, it's more like, oh yeah, that would be interesting, that would be fun. >> how many matches have you been able to make? >> we have over 1 million people

and it's growing every day. we have thousands of matches. >> reporter: she shows us how the matches work. >> this is twin search. these are all the people who have selected the exact same facial features. >> i see. >> reporter: nimah is bringing people together from all over the world to meet face-to-face. >> i signed bun a month ago. >> reporter: shannon from ireland and sarah from sweden. >> hi! oh my god. >> oh my god, you look just like me. >> it's my twin sister. >> reporter: here in the u.s., ambra and jennifer meet for the first time in houston, texas. >> twin strangers. bond very quickly because they're looking at a face they've been looking at their whole life. it's familiar to them. >> i live in tacoma, washington. i

australia. >> reporter: we wanted to see the doppelganger bond up close and personal. "nightline" paired up with twinstrangers.com to go behind the scenes of one of their meetups. brigham bear frringing amber fr perth, australia, and maddy from tacoma, washington, to l.a. even i was confused. >> hi. how are you? hi! you're double trouble. nice to meet you. >> nice to meet you. i'm amber. >> i'm maddy. >> amber, maddy, you guys are adorable. >> nice to meet you. >> whose idea was the purple? >> maddy's. >> me. >> first reaction when you saw the photo of each other on the site? >> i never really met anyone that looked like me. so seeing her picture is kind of weird. that was the first time i'd ever seen anyone that even looked remotely similar to me. >> much less dead ringer. >> yes. they sent me a photo of maddy to ask if i thought we were

started loading and i thought it was a picture of me. then the rest loaded and i was like, wow, that's insane. >> what piqued your curiosity? there are an equal number of people thinking, no, i would never want to meet somebody like me. >> just thought it would be fun, why not. see if there's someone that's out there. >> fun, not creepy? >> right, yeah. >> yes, i thought it was fun. >> were there any freak-out moments? >> moments where we go to do the same thing at the same time. like brush our hair. take a bite of food tame. >> when we were eating breakfast together, everyone freaked out because we ate something the same way. >> like twins separated at birth. >> yes, maybe. >> tell me a little about what you do for a living what background if. >> i cut hair for a living. >> i learned some make nun cosmetology school. that's what she does. we graduated the same year. >> you have the same laugh. >> now we're trying not to laugh. >> reporter: they spent the weekend together sightseeing in

times even they've been confused. >> you guys look like twins. >> absolutely. we're related almost. it's crazy. >> what was the reaction? gut reaction? >> first thing, oh, crap. >> yeah. you've got to really know who -- from behind you don't even get it. at first, you know, it was all about the looks. then after hanging out with them a few days, it's more than just the makeup, it's more than just the hair. they start doing things in unison. it's kind of like, okay, stop. right? are you doing that on purpose? >> reporter: we wanted to see if there's a genetic reason for their similarity records we asked amber and maddy to take a dna test that ancestry.com agreed to process for free. in just a few weeks the results are in. guess what? they are 100% not related. but they do have similar european roots. despite the results, they say their newfou b

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finally tonight, as you all know a formal truce has been called on a fierce political battle. the vermont senator pledging to join forces with hillary clinton. at long last. here's abc's david wright with our political punch. >> reporter: he lost the last primary nearly a month ago and the writing has been on the wall even longer than that. >> secretary clinton has won the democratic nominating process -- [ cheers and applause ] >> reporter: only today about bernie sanders finally concede. >> hillary clinton will make an outstanding president, and i am proud to stand with her today. >> reporter: an anti-climactic end to one of the longest, bitterest primary fights in

years. >> i don't believe that she is qualified. >> reporter: one where he accused her time and again -- >> you know -- >> excuse me, i'm talking. >> reporter: of embodying the cancer at the heart of american democracy. >> our average contribution is $27. i am very proud of that. >> reporter: today these two democrats set all that rancor aside. >> we accept $27 donations too, you know. >> reporter: the most recent abc news poll found that three out of four sanders voters say they will vote for clinton. but today donald trump tweeted, bernie sanders endorsing crooked hillary clinton is like occupy wall street endorsing goldman sachs. the question now, will bernie's voters agree? i'm david wright for "nightline" in new york. >> the ultimate, if you can't beat 'em, join 'em. thanks for watching abc news. tune into good morning merge. as always we're online at

"nightline" facebook page. that was really a great dinner, huh? yeah, yeah. happy anniversary. hey, you know what i was thinking? since this is our tenth anniversary, why don't we let the kids stay at grandma's and grandpa's all night, if you know what i mean. hey, hey, we could watch our wedding video.

i guess you don't know what i mean. no! come on. why? why, why? well, for one thing, watching our wedding video might make tonight seem like a honeymoon. gimme. sit down. you don't know how to use this. you never did, really. can we fast-forward through the chicken dance, please? unless this turns you on. [mumbles chicken dance] you can save that for later. mmm. oh. oh, see, i love this. isn't this romantic? yeah, yeah, yeah. oh, look who i get. what, did you hit something? did you hit something? no, no, it's still going. then why am i seeing football?