A swarm of FBI agents searched the Gaithersburg, Md., home of Gary Giordano, who Aruba officials say is no longer cooperating in their investigation of the disappearance of his traveling companion, Robyn Gardner.
Investigators in Aruba are poring over surveillance tape and talking to witnesses, but none have provided conclusive evidence of what happened to Gardner, 35, who is presumed dead.
Suspicions regarding Giordano have risen after officials revealed that two of his ex-girlfriends had placed restraining orders against him.
One alleged, in court documents, that he choked her and stuck his hand down her throat after she objected to his swinger lifestyle. The other alleged that he posted photos and letters about her on neighbors' mail boxes, "threatened me ... and told me 'the world would be better off' without me and he could help."
Authorities were trying to determine whether Giordano had bought a life insurance policy in Gardner's name, ABC affiliate WJLA-TV also reported. An ex-girlfriend told investigators that he forced her to sign a policy listing him as the beneficiary, according to the report.
Gardner's more than year-long, on-and-off relationship with Giordano, who is scheduled to appear in an Aruba court Monday, also was volatile, her friends said.
"It's been a real rollercoaster friendship. It's pretty hot and cold. One day nice, and the next day, not so nice," Christina Jones, Gardner's roommate and best friend, told ABC News' "Good Morning America." He also habitually sent Gardner angry text messages, she said.
On July 31, Giordano and Gardner checked into a Marriott hotel on the Dutch Caribbean island.
Starting last Tuesday, police, fire and search teams scoured the caves and thick brush at Baby Beach where, Giordano said, he and Gardner were snorkeling Aug. 2 when ocean currents pulled her away from him.
After initially granting Giordano permission to leave Aruba, island police detained him just minutes before he was scheduled to board an Aug. 5 flight out of Aruba. Police doubted parts of his story, including the lapse in time between when witnesses saw the pair and Giordano reported Gardner missing.
Giordano denies any wrongdoing, said Michael Lopez, his attorney in Aruba.
Former FBI special agent Brad Garrett, an ABC News consultant, told "Good Morning America" that Giordano fits the profile of an "obsessional stalker."
"Their self-esteem is really tied up in controlling whoever is in their lives," Garrett said. "What happens is they push people so far [that] they pull back. When they pull back, he becomes more obsessive. He becomes more violent."
Searchers wound down their search for Gardner Friday at an abandoned phosphate mine on the island's rocky, cactus-covered southern tip, where Baby Beach is situated, The Associated Press reported.
Earlier on Friday, Aruban officials said they do not believe Gardner is alive. Having recovered her passport, police said it's unlikely that she could have flown out of Aruba without it and they they have no evidence that she left by boat.
The Dutch-based judicial system in Aruba, where Alabama teen Natalee Holloway disappeared in 2005 and was never found, would allow the courts to extend Giordano's detention for up to eight days following Monday's hearing. After that, prosecutors must provide substantial evidence of the suspect's guilt to win a court order for Giordano to be held up to 60 days while they prepare to file a case against him.