New Haven Police Chief James Lewis said at a news conference Tuesday night that police executed a search warrant for the Middletown apartment of Raymond Clark, a 'person of interest' in the slaying of Yale student Annie Le. 'We took him into custody to gather evidence from his body and his person,' Lewis said. 'If he cooperates, he'll be released this evening.' Lewis said the search warrant was for Apartment 1A at 40 Ferry Street in Middletown, where at 10:16 p.m. about 20 New Haven, state and federal law enforcement officers, armed with the search warrant, entered the apartment building. Seven minutes later, an unmarked police car pulled up to the apartment building's front door, and another minute later officers escorted a man in a white T-shirt out of the building and placed him in the car. The car then was driven off. Lewis said police have looked at 700 hours of videotape, interviewed 150 people and gathered 150 pieces of evidence in the case. He also said that police have not ruled out whether others were involved in the murder. 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's Web site. 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. Clark is a 2004 graduate of Branford High School in Branford, where he was on the honor roll. He appears to have no criminal record in Connecticut. He was issued a speeding ticket when he was 18. Le was asphyxiated and her body was stuffed into a barely 2-foot-long crawl space inside the research laboratory where she had gone to work on the day that she disappeared, sources told The Hartford Courant earlier Tuesday. Chief Medical Examiner H. Wayne Carver II held off Tuesday on releasing the cause of death in Le's case, saying he did not want to influence the investigation. But a source told The Courant that Le was asphyxiated. For days, investigators searched 10 Amistad St., a research building near Yale's medical school, looking for clues to what 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 Tuesday morning, a source said. Police had to remove part of the wall in a laboratory to access the crawl space. The source said 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 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. Other evidence seized at the scene and evidence from the lab technician who is the apparent focus of the investigation is also being analyzed. Authorities also are trying to determine if Le was sexually assaulted. Authorities have been watching the lab technician'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. When a Courant reporter asked an official parked outside the complex whether he was there as part of the Le case, the reporter was told: 'I can't confirm or deny that rumor.' When a Courant reporter knocked on the door early Tuesday afternoon, a man inside would not open the door but said he didn't know the man in question. A person in the apartment's leasing office said she had been instructed not to talk. Neighbors said that authorities in unmarked cars first arrived Monday afternoon and frequently followed and pulled over drivers in the complex. The 'person of interest' has worked for the Yale Animal Research Center for at least four years. It is unclear what connection, if any, he had to Le, other than providing and caring for the animals, mostly mice and rats that she used in her lab work, a source said. 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 at the North Ritz Club 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. On Tuesday night, 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 before a media throng, left without taking questions. The church of which he is pastor was not identified. Le was reported missing Sept. 8 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 writer Matthew Kauffman contributed to this report. 