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>> reporter: 48 hours after she arrived in aruba, robyn gardner's getaway vacation had spiraled into a disaster. back in maryland, her boyfriend, richard forester, was frantic after losing contact with robyn for two days. finally her brother called saying she was missing at sea. and with that came another piece

of news, as hurtful as it was stunning. >> he said that she was down in aruba with her friend, gary. >> reporter: robyn had lied to him. she wasn't in aruba with her family, she was there with another man, gary giordano. robyn had told richard about gary before. but she had also told him that gary was not interested in women. >> she'd mentioned that he was a gay friend. all that mattered to me was, okay, what's going on and how do we find her? >> reporter: that's what the aruban police wanted to know. and gary giordano gave investigators his version of what happened on the day robyn disappeared. he said they drove from their hotel to an area called baby beach where they stopped at this restaurant. it's a story backed up by security video. here are gary and robyn arriving around 3:00 and then leaving about an hour later. gary then took investigators to an isolated spot nearby called

mankey beach where gary said he and robyn went snorkeling. robyn, he said, cut her foot on a sharp rock just before they went in. police say giordano told them the water was rough and at some point he felt he was being pulled out to sea. he swam back thinking robyn was right behind him, but when he got close to shore he turned and she was gone. by now it was after 6:00 p.m. security video at the restaurant, now closed for the day, shows gary returning, apparently to look for help. police put boats and divers in the water. there was no trace of robyn. and so questions quickly arose. was this an accidental drowning? or was it something else? >> they did not go snorkeling. you know, this is not robyn. >> reporter: her roommate and hairdresser christina jones doubted that robyn, who spent so much money or hair color and extensions would ever go

snorkeling. >> there's no way that she would get into the ocean, you know, after spending a couple grand on her hair. >> reporter: quickly aruban police found inconsistencies in the story gary giordano was telling them. solicitor general taco stein. mr. giordano says he was snorkeling with ms. gardner and that the water was rough. >> that's what he told us, indeed, but it was a very calm day. there was no currents, no waves, nothing like that. >> reporter: police concluded that giordano's story was at the very least highly suspicious and in aruba, which is part of the netherlands, police can hold you just on suspicion. but giordano wasn't in custody. so police went looking for him. >> when he became a suspect and we decided to arrest him he was already in the airport. >> reporter: gary had gone to the airport and changed his ticket to take an earlier flight back to the u.s.

according to police, the ticket agent asked him where his traveling companion, robyn, was. >> he claimed that she took a later flight. which is of course, odd. >> reporter: but that was not the only suspicious thing gary giordano did. police discovered gary had taken out an insurance policy on robyn gardner. a policy that would pay $1.5 million in the event of her accidental death. and the policy's beneficiary? gary giordano himself. and just two days after robyn went missing and before he tried to leave aruba, gary inquired about how to claim the insurance payout. >> is it normal to insure somebody's life and make yourself the beneficiary? or do you make the relatives the beneficiary? >> reporter: so police arrested gary giordano at the airport just as he was about to fly home to maryland. an aruban judge ordered gary

held in custody while police investigated further. >> gary, over here! >> where's robyn? >> reporter: he was now a suspect in a murder investigation. aruban police also asked the fbi for help. and agents searched giordano's home looking for evidence. so who was gary giordano? he was a successful businessman running his own job placement agency and living in a $1.2 million home in suburban maryland. and gary, as it turned out, was not gay. the 50-year-old divorced father of three met robyn through an online dating website. they'd been seeing each other casually for more than a year and robyn had chosen not to tell her boyfriend. >> she told me her and gary were not intimate. he might have weaseled his way into her life but not into her heart. >> reporter: while investigators were looking further into the story gary giordano was telling,

back in the united states the fbi was looking into his background. court records in the state of maryland shed some light on giordano's life. back in 2003, gary giordano and his first wife went through a nasty divorce, trading allegations of abuse in court papers. after becoming single, he ended up with orders of protection against him from two different women. the picture that seemed to be emerging from some of those who had dated gary giordano was that he was capable of being charming one moment, a monster the next. that's certainly what christina says robyn told her. >> he was aggressive sometimes and verbally abusive. >> reporter: case in point, just months before the aruba trip, gary invited robyn to go on a cruise. she initially agreed but then canceled when her boyfriend objected.

christina says robyn showed her some text messages gary had supposedly sent after robyn bailed. >> he said that he was going to ruin her life, he said he was going to get ahold of richard, he, you know, was going to let everyone know who a whore she was. >> reporter: but three months later robyn agreed to go to aruba with gary. >> and she just was like, look, i can handle it. you know? i'm going away. >> reporter: going away never to be seen again. so what could have happened to robyn gardner? "dateline's" unsolved case squad, a team of veteran investigators, went to aruba, to the very places where robyn gardner spent her last moments looking for answers to the strange disappearance of the woman with the golden hair. coming up -- >> this was nothing, nothing like what i pictured. >> "dateline's" investigators hit the beach in aruba. and later, tough questions for the prime suspect in robyn's disappearance.

why is it the police couldn't find a single witness who saw you in the water with robyn gardner?

>> reporter: in the days and weeks after robyn gardner vanished here in aruba, the only things that surfaced were rumors and suspicion. no sign of her or her body. and robyn's travel companion turned suspect in her disappearance, gary giordano, was ordered held on suspicion of her murder in the island's only prison. a beautiful blond, missing in aruba. robyn gardner's disappearance set off headlines across the country and around the world. and for many it brought back

memories of a similar episode six years earlier when another american disappeared on this same island. her name in case you don't remember was natalee holloway. natalee was 18 on her senior class trip from alabama in 2005 when she disappeared. her body was never found. a local named joran van der sloot, the last person seen with natalee, was twice arrested but never charged. >> gary, over here. >> reporter: so what was the evidence investigators in aruba felt warranted the arrest of gary giordano? there was that $1.5 million insurance policy gary had taken out on robyn gardner's life. there was his attempt to leave aruba earlier than scheduled. his troubled past with women. and this. investigators had gone to the trouble of staging an elaborate re-enactment of robyn's last hours, complete with actors, with gary's statements to police

as the script. investigators just didn't buy it. mr. giordano's story may be in certain places difficult to believe, but it's not impossible. >> no, it's not impossible. but what we do know is that he lies about a number of things. he lies about the surf. he lies about the current. he lies about the winds. so there is a lot going against him. >> reporter: two months after robyn was last seen, two members of "dateline's" unsolved case squad went to aruba to check out gary giordano's story. nbc news consultants duane stanton, retired homicide detective from washington, d.c., investigated chandra levy's murder. and yolanda mcclairy, crime scene investigator in las vegas and a model for the character on the hit series "csi." >> so we're heading out of the marriott -- >> reporter: our team retraced the couple's route starting at the marriott where gary and

robyn stayed on beautiful palm beach. and then they drove south on the island toward baby beach, the area where robyn was last seen. driving past mile after mile of beautiful beaches, our investigators wondered why robyn and gary, who only planned to be in aruba for three full days, would drive all this distance to go to a beach. >> that sure seemed like a long time to get here. >> more than 18 miles and it took approximately an hour. >> reporter: next stop? rum reef, that beachside bar where robyn and gary had lunch and the last place robyn was seen alive. our team had watched the security video showing the couple arriving the afternoon of august 2nd at 3:07 p.m. then, almost an hour later, gary going out to the rental car, putting something into a blue cup. that brief trip to the car got the attention of our investigators. >> what was in that cup?

as an investigator, you want to look and see if a foreign object was maybe introduced to her system, a narcotic, a drug. that's a possibility. >> reporter: from rum reef our team followed the trail gary told police he followed to take robyn snorkeling. he said they went not to popular baby beach, which was only steps away, but to this much more remote and rocky spot called mankey beach. our investigators were struck by the spot when they saw it. >> i mean, this -- this was nothing, nothing like what i pictured. >> if i'd come to this location, i want to be alone. we're back here right now by ourselves, i could accost you, i could take you and go into the water, you could scream. >> no one would hear me. >> no one would hear you. and just looking around --. >> reporter: our team also looked closely at gary's statement to police. he said that while snorkeling the waters got rough. that he tapped on robyn's leg to signal they should return to shore. while swimming back, gary said

he hit a rock and was busy saving his own life. and when he got back to shore, he says, robyn was nowhere to be found. and our team was puzzled by what gary giordano did after he said robyn didn't come out of the water. they'd seen that security video time stamped at 6:16 p.m. it shows giordano returning to the bar, he says, to try to find help. our team wondered why isn't he moving faster? and why doesn't he look more worried? >> from an investigative perspective, i have huge problems with his lack of urgency here. >> reporter: finally, our team asked if no one saw either robyn or gary in the water, is it possible that before gary reported her missing at 6:16 p.m. he could have killed her and moved her body to another location on the island during

the two hours in which he's unaccounted for? aruban authorities have mobilized search teams and cadaver dogs to search the acres of cactus and brush within several miles of the beach trying to answer exactly those questions. >> think about it. if you're trying to dispose of a body, again, what better place would there be to come than a place just like this? >> it could literally be here forever until somebody happens to come across it. >> exactly. >> reporter: you've been here a few days, have you drawn any conclusions? >> a few. one is i don't believe she's in the water. i think she's very well hidden somewhere on this island. >> you don't think they ever went snorkeling? >> i don't. >> i don't. >> reporter: but there's another way to view all the red flags surrounding gary giordano. and you're about to hear it from his attorney who says gary giordano is an innocent man. coming up --

>> reporter: did your client kill robyn gardner? >> absolutely not. this was a drowning. >> reporter: but can he convince our unsolved case squad? when "missing in paradise" continues. but i found myself using three times more than you're supposed to and the clothes still weren't as clean as with tide. so we're back to tide. they're cuter in clean clothes. thanks, honey. yeah. you suck at folding. [ laughs ] [ female announcer ] just one dose of tide original liquid helps remove food stains better than an entire 40 load bottle of the leading liquid bargain brand. that's my tide. what's yours?

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>> reporter: on the island of aruba, the tourists keep coming. headlines of a missing american it seems are no rival for the never-ending sun and warm as bath water seas. robyn gardner's loved ones remained in limbo, not knowing what had happened to her. while gary giordano's legal limbo behind these prison walls was soon measured in months. but soon giordano had a compelling voice in his corner. >> he's innocent. this whole case has been one tremendous nightmare for him. >> reporter: jose baez, best known as the defense attorney who helped gain acquittal for accused killer casey anthony, is a member of giordano's legal team. >> did he kill robyn gardner? >> no. this was a drowning. she certainly would have appeared by now had the situation been otherwise. >> reporter: so the proof that there wasn't a crime is that there hasn't been a body?