NEW HAVEN, Connecticut—Yale graduate student Annie Le died from traumatic asphyxiation due to neck compression, the office of the chief state's medical examiner said Wednesday.
Le's body was found Sunday in a university research building, five days after she disappeared.
"We took him into custody to gather evidence from his body and his person," Police Chief James Lewis said at a press conference.
New Haven police spokesman Joe Avery said Clark was released to his attorney this morning after he complied with requests for DNA samples. Avery did not know his whereabouts and said he was free to go wherever he wanted.
"We're committed to proceeding appropriately with the authorities with whom we are in regular communication," said David H. Dworski, Clark's attorney.
The public defender's office in New Haven is also consulting on the case.
Officers wearing gloves were seen entering and exiting Clark's apartment building Wednesday morning.
Lewis said that the warrants were for Clark's person and for Apt. 1A at 40 Ferry St. in Middletown. At 10:16 p.m., about 20 New Haven, state and federal law enforcement officers entered the apartment.
An unmarked police car pulled up to the apartment building's front door, and then officers escorted a man in a white T-shirt out of the building and placed him in their car.
Clark shares the apartment with his girlfriend, Jennifer Hromadka, whom he is engaged to marry in December 2011, according to the couple's wedding Web site.
Clark moved to Middletown from New Haven six months ago, where he shared an apartment with his girlfriend and three cats, according to former neighbor Taylor Goodwin, 16.
Lewis said that police have looked at 700 hours of videotape, interviewed 150 people and gathered 150 pieces of evidence in the case, some of which have DNA on them. He said that police are "trying to narrow down the list of suspects in this horrendous crime," and added that they haven't ruled out whether others were involved in the slaying.
When asked what led police to Clark, Lewis said, "We narrowed it down to who had access to this building and who was in what room and where."
Clark worked as an animal technician for the expansive Yale Animal Resources Center, which "provides for the daily care of all animals used in research at Yale (95 percent of which are rodents)," according to Yale University's website.
The center, which is accredited by the Association for Assessment and Accreditation of Laboratory Animal Care, coordinates the procurement of research animals, houses animals at multiple sites around the campus, and offers various scientific services to researchers, including breeding, tissue collection and analysis, animal restraint during experimentation and euthanasia.
In a recent school directory, the center had 67 people employed as animal technicians.
Le was asphyxiated and her body was stuffed into a barely 2-foot-long crawl space inside the laboratory where she had gone to work on the day that she disappeared, sources have told The Courant.
For days, investigators searched 10 Amistad St., a research building near Yale's medical school, looking for clues to what had happened to the petite, 24-year-old student who was supposed to have been married last weekend.
It wasn't until five days after her disappearance that members of the state police crime squad, with the assistance of a cadaver dog, discovered her fully clothed body. She was wearing the same clothes seen in a video of her entering the building last week, a source said.
Police had to remove part of the wall in a laboratory to get access to the crawl space. The source said that evidence recovered from the crime scene indicated that Le was killed in a different room in the basement and then moved to a second room where the crawl space was.
The source said that only someone with intimate knowledge of the layout of the laboratory would have been able to access the crawl space.
The source said that tiny droplets of blood were found in one of the laboratory rooms where police now believe that the slaying took place. The blood is being analyzed at the state forensic laboratory. Authorities also are trying to determine if Le was sexually assaulted.
Because there is limited access to the research laboratory, investigators were able to determine relatively quickly who was in the building when Le disappeared. Le was last seen about 10 a.m. Tuesday morning entering the building. She never left.
FBI agents interviewed anyone who had access to the lab and gave many of them polygraph tests. Sources said the lab technician failed at least one polygraph test.
Investigators didn't lock down the building until the weekend, meaning that people walked around and possibly through the potential crime scene for four days.
Investigators had attempted to bring a cadaver dog into the building earlier in the week, but because of the large number of animals in the laboratory, the dogs were unable to do a thorough search.
Le, from Placerville, Calif., was to have been married Sunday in Syosset, N.Y., to Jonathan Widawsky, a graduate student at Columbia University in New York. Police have said that he is not a suspect and is helping with the investigation.
Authorities have been watching Clark's Middletown apartment for two days. Late Tuesday, television camera crews and other members of the media clogged the street around the Wharfside Commons apartment complex in the city's North End.
Ivan Hernandez, 22, lives in the apartment directly above Clark's. "He was a quiet man," Hernandez said late Tuesday night. "It's crazy to think that something serious like that was right below me." Hernandez said that Clark, whom he did not know by name, had lived there since before Hernandez moved in seven months ago. "I would see him sitting in front or walking to the car with his girl," Hernandez said. "He was just really quiet."
On Tuesday, a local pastor, the Rev. Dennis Smith, read a statement from the Le and Widawsky families. He thanked the Yale community, saying on behalf of the families: "Our loss would have been immeasurably more difficult to deal with without your support." He said their thanks go out to everyone in the Yale community, from President Richard Levin, to students, to the Vietnamese Student Association. He said that the families also wanted to thank the FBI and the state, New Haven and Yale police departments.
Smith, standing on the steps of Woodbridge Hall on Wall Street before a media throng, left without taking questions. The church of which he is pastor was not identified.
Le was reported missing Tuesday evening by her roommate. Yale police called in the FBI to assist in the initial investigation. At first, police were unsure if Le had just gotten cold feet and didn't want to get married or had been the victim of a crime.
At least two searches of the building were conducted without finding her. On Saturday, police did find some blood-stained clothing hidden in a ceiling panel in one of the laboratories. It is unclear if the clothes are connected to the crime.
In the hunt for potential evidence, authorities set up a makeshift triage center behind the Amistad Street building, and investigators wearing full-body suits and masks shifted through bags of medical waste removed from the building.
Investigators also searched the Connecticut Resources Recovery Authority's trash facility on Maxim Road in Hartford over the weekend trying to find trash that might already have left the Yale building.
The building at 10 Amistad St. is part of the university medical school complex about a mile from Yale's main campus and is accessible to Yale personnel with identification cards.
A network of about 75 video surveillance cameras are trained on every door.
Courant staff writers Josh Kovner, Alaine Griffin, Dave Altimari, Hilda Muñoz, Matthew Kauffman, Jeffrey B. Cohen and Stephen Busemeyer contributed to this story.