and his mother in custody in mexico. allegedly fleeing the country to avoid arrest after violating his probation for killing four people in a drunk driving accident. investigators claiming the mother and son planned to make a run for it. ethan undergoing a dramatic transformation. plus, it looks like a scene straight out of "mad max." but these crash queens are ready to rumble in real life. we're at the demolition derby with these moms who carpool by day, crash cars on purpose by night. you think you've found your ideal hotel? >> he's the guy going viral for hilarious commercials. >> trying to do so many things at the same time? >> tonight he takes us inside the world of spokesperson stardom. >> one tuck in, and one tuck out. but first, the "nightline" five. >> what you doing? >> prepping for my boss's party

number 1 in just 60 seconds. good evening, thank you for joining us. tonight the stunning revelations about the mother and son on the run and the takedown in mexico. the afluna teen ethan couch, who killed four people drunk driving and his mother. they're in custody.

before their escape. matt gutman has the latest. >> reporter: the three-week manhunt for the privileged teen ending with ethan couch's arrest on this gritty street in puerto vallarta, mexico. you see him cuffed and loaded into a police van. this photo confirming 18-year-old couch and his mother tanya were detained monday evening. the mother who refused to sit still to be photographed herself, apparently changing her look. the son, dyeing his blonde hair black. the trance formation, so different from the childish looking teen who pled guilty to killing four people in a drunk driving krar. >> there's four or fiver kids. oh, yes, there's another child in the ditch. e on, my god. >> in the sentencing, his legal team claimed he suffered from affluenza, too rich and too spoiled to know right from wrong.

probation and no jail time. a break for investigators coming on christmas eve, a week after this post was released, offering a $5,000 reward for any information, saying that he was on the run in this black ford truck, belonging to his mother tanya, who was also missing and believed to be with him. >> they have probably driven that to the border and crossed over. >> reporter: adding that before they set out on there 2,200-mile trek, they even had something akin to a going-away party before they left town. >> reporter: mexican authorities were alerted on december 26th and last time they got him. >> it's like trying to find a needle in a haystack. >> reporter: according to officials when the pair arrived in puerto vallarta, they checked into this beachside resort. >> a tremendous amount of tourists down there, so american people were prevalent everywhere and they wouldn't be somewhere they would stick out. but then they relocated to this

quiet street. but not many americans in this neighborhood where residents said ethan stuck out. eyewitnesses say they were escorted by police out of that door, their hands cuffed behind their backs. they said they didn't resist, didn't struggle. two months ago, we tried to track him down. he was on probation. he'd never apologized for the deaths. >> they don't come to work at regular hours. they don't keep regular hours. them. >> but he wasn't looking -- you don't want to answer any questions! he soon surfaced again in this twitter video that went viral. it appears to be couch at this boozy party, possibly violating his prorkz. it prompted couch and his mother to flee, ditching his check in with his probation officer. tonight he's in custody, but the kid who set off an international

days in jail. he'll be out of prison as soon as he turns 19 in april. >> the next step for prosecutors is to try to move this case from juvenile court to adult court. so if there's any other kind of violation here, he could be facing serious time behind bars. >> reporter: it all started on the night of june 15th, 2013. his blood-alcohol was three times the legal limit when he got behind the wheel of his father's souped-up, red pickup truck after a night of partying. gunning it to 70 miles an hour, he lost control of the vehicle and swerved into a ditch, plowing into a group of people there. bodies scattered hundreds of feet. 15-year-old lucas mcconnell survived the crash. >> you were the sound of metal crunching, glass breaking. >> glass breaking and tires screeching. the car that we were in got hit and we got shot across the road.

the back window was commeel shattered. >> lucas's father pulled up to the crash scene just moments later. >> it was chaos. there were people lying around, injured, hurt, dead. people yelling screaming help me. >> the teen behind the wheel, ethan couch, walked away from that mangled truck. >> once ethan couch was found, the story came together quickly. >> not only was he drunk, but there were traces of thc, val yum and some other drugs? >> right. which were bad enough on their own, but combine those with challenge, just a recipe for disaster. >> the assistant district attorney came onto the case just a day after the crash. he charged ethan with everything he could, including four counts of intoxication manslaughter. he wanted the poor little rich kid to do some big-boy time. we were hoping for and asked for 20 years.

juvenile. during the defense team, his defense team dropped that curious term, a influenza. the judge sentencing him to probation and time in a rehabilitation facility. the couches have settled lawsuits without admitting any wrongdoing but not before depositions were taken in one last case. >> ethan couch. >> for the first time, the boy and his parents at the center of this story were forced to speak. >> taken val yum, hidio code own, marijuana, cocaine, xanax. i think i tried ecstasy once. pretty sure that was it. >> half the time his parents testifying they allowed their young son a lot of freedom, including driving at the age of 13. >> you understood if he was at any time he was under 16, he was

>> yes. >> nevertheless, you allowed that behavior to happen, correct? >> yes. >> i just kept asking because i wanted to. eventually they started letting me drive, just to like the corner store by myself. >> before the deadly crash, ethan was required to complete an alcohol awareness course and eight hours of community service within 90 days of a previous incident. >> we didn't do the community service. >> you understood, did you not, that he was likely to continue the drinking and driving if there weren't consequences? >> i should have known that, yes. i really didn't think that was happen again. >> at one point, ethan's parents branded in the media as the worst parents ever. >> i don't think we're profoundly dysfunctional. >> did you teach ethan that wealth brought privilege? >> i don't believe that i ever intentionally tried to teach him

>> do you recall ever disciplining ethan for anything? >> sometimes i would take little things away from him. or we would just discuss the problem. >> when is the last time you recall disciplining ethan for anything? >> reporter:ut now ethan and his mother tanya are both in custody and said to be deported back to the u.s. within the next consequences. >> suspicion that his mother was assisting him and helping him. which has proven true. >> reporter: so far authorities haven't uncovered any evidence that ethan's father is involved, but they say they have enough reason to punish the mother. they expect her to be charged with the third-degree felony of hindering an apprehension. >> amazingly, his mother could face more jail time than him at this point. because he's in juvenile court. he can only face up to 120 days.

up to 2 to 10 years behind bars. >> reporter: for "nightline," i'm matt gunman, in puerto vallarta, mexico. next, we're going to a demolition derby, where some of the most aggressive drivers might surprise you. and later, meet the trif ago guy. what's it like getting catapulted to fame through a funny ad campaign? wildlife rescue workers open up a lot of dawn. tough on grease...yet gentle. dawn helps open...

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talk about a double life. at home the women you're about to meet are moms. but at night, they switch from carpool duty to demolition derby, and they're dead serious

here's abc's david wright catching up again with these crash queens. >> a rumbling arena, a roaring crowd, and gladiators gunning gas-guzzling machines. competitors ready to destroy each other. this is metal mayhem. $20,000 in prize money at stake. among those drivers reffing their engines are moms. some of the toughest women on wheels. >> any woman that gets in a dirty car the first time either is hooked or -- >> meet kim potocki, mother to two girls, part-time little league coach. >> are you practicing? >> yes. >> reporter: who, when she's not carpooling the kids, can crash them up with the best of them. >> it's an adrenaline. it's something different. you don't normally get to go hit people.

her biggest competition so far. where she'll be squaring off against 300 top derby drivers, including her husband, chris. >> not the first time that's happened. >> reporter: building the cars from scratch is a family affair. the kids pitching in. >> the cars are engineered to do one thing on the road and we're doing something different with them to do what you need it to do, to last, that's part of the fun of it. >> that will get me to the floor. >> reporter: they strip out anything that can break or burn. >> he's cutting the old motor mounts off because they were welded on the frame. >> reporter: mom's car has to survive crashing into this. that's vicki schutte. >> in 15 years, i've won three features. >> reporter: a welder by day, a useful trade in this sport. her destructive tendencies have paid off. >> i was the only girl that's ever one my hometown derby, so

accomplishment for me. >> let's start stripping. >> i've been doing the demolition derby since i was 19 years old. my dad has done it since before i was born. >> reporter: her two sons, 14 and 8, already behind the wheel. >> do you have a license? >> not yet. [ laughter ] >> reporter: her uncle runs metal mayhem every year. >> are you ready! >> reporter: demolition derby can be a dangerous game. after all, the main objective is crashing. >> it's just whichever car keeps moving forward? >> the last car to make a hit. >> the guys have pretty much stopped the derby. >> do injuries happen? >> they happen. >> we have a list of rules that we have to build the car to, so they're looking to see that everything is built properly and that the car is safe.

flying colors, but vicki's car has a problem. >> the spray foam. >> i don't know. you're kind of a bad ass, aren't you? >> reporter: which leads to a frenzy of modifications as fast as possible. >> i need you to pull out as much foam as you can. >> reporter: her car is ready. >> i'm hoping not to have a small error take me out. >> reporter: meanwhile, kim is getting revved up for battle. they may call this the powder puff heat, but there's nothing soft and dainty about it. for vicki, a serious hitch. exactly what she was worried about. her drive shaft fails. her car is a sitting duck. >> the minute before he said go, i made one hit and was done. i was devastated.

because it was a lot of hard work was put into that car. >> good job! >> reporter: kim, muddy but victorious, moves on to the finals. >> $20,000 for first place. >> reporter: but there's no time to celebrate. >> this point right now is the most pressure, it's the biggest. everybody trying to work to get the other and make it back out. >> reporter: having already survived some serious scrapes, her car has to be fighting fit for the main event. >> the wiring we're trimming and clearing, we're getting everything done, but this is it. it won't be pretty, but she'll be functional. >> reporter: and her former rival vicki shows up to help. >> vicki's helping. she didn't make it and now she's helping. >> reporter: the sisterhood kicking in, because that final

50 drivers, a lone woman, against 49 men. >> do the men go after the women? >> it can be. i mean, we're easy targets, apparently we don't know what we're doing, so -- [ laughter ] we like to prove them wrong, that's for sure. >> reporter: the main event. >> come to michigan, girl. >> yes, sir. >> reporter: once they put on those helmets, it's tough to tell the men from the woman. it's a free for all. the last, not kim's day. she may be back to driving the carpool tomorrow. but already she's thinking about her next metal mayhem. i'm david wright for "nightline" in illinois. and next, around the world with the trivago guy.

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>> finally tonight, think of your favorite commercial and you'll probably think of a favorite spokesperson too. the right face can make or break an ad campaign, and trivago definitely lucked out with their guy. his off-beat appearance >> did you notice that there's so many prices out there for exact same room? >> reporter: tim williams is known as the trivago guy. >> when i shop in miami, i need to be connected.

to know what his deal is. >> i come from houston, texas, and made my way to new york to study acting. i working on my so-called life with claire danes. then the sopranos. >> reporter: but it's commercial success that has women and men obsessing over his laid-back look that also comes with a little criticism. >> tuck in your shirt, you badly dressed trivago guy. okay, is that enough? >> reporter: joins the ranks of progressive's flow. the most sbrg man in the world. >> stay thirsty my friends. >> making a ceer outf advertin ogne company. he m o rm y mew yor id, are you crazy! you don'speak german

d then ended upn av show tr slated to goodesim bad times. i had to shootmonday and o thursday and fri i hado shoot ivago. and then we realized thatokay, none of the belts seem to be fitting the belt loops. so we went out without the belt. >> trivago does the work for you. >> reporter: a wardrobe malfunction. put him in the world of the advertising elite. >> speaking of celebrity, it was the late american politician in newspaper editor horace greely who said fame is a vapor. riches take wings. only one thing endures and that's character. thank you for watching. tune in "good morning america" first thing tomorrow. and as always, we're online 24/7

and on abc.com. now on ok tv, sylvester and stall lo hit the same market. carmen electrifying and here comes honey boo-boo. we have the front seat. jennifer lawrence dishes about her very first sex scene with chris pratt. how she used her mom and jada pinkett smith's shocker on the red carpet. and dwayne johnson opens up with depression. >> it wound up being one of the greatest chaptsds in my life. plus are these guys really ridiculously good-looking days over?