NEW HAVEN, CONN. — As FBI agents and Yale University police combed the basement of a laboratory building for missing bride-to-be Annie Le, the man accused of killing her moved among them in an apparent effort to cover his tracks, a law enforcement official familiar with the investigation said.
That behavior aroused suspicions about Raymond Clark III, but the final piece that led to his arrest Thursday was the discovery that evidence in the ceiling and in the crawl space where Le's body was found contained the DNA from both Le and Clark, according to the law enforcement official who spoke on the condition of anonymity because the investigation was ongoing.
Clark, 24, was arrested at a Super 8 Motel in Cromwell, Conn., and charged with murder.
One investigator, among a group who were in the lab interviewing employees and students shortly after Le disappeared, reported witnessing Clark trying to hide lab cleaning equipment that they later discovered contained blood spatters.
Clark was observed cleaning up areas Le was in before she was reported missing, the law enforcement official said.
Sources familiar with the investigation said that a combination of factors led to Clark's arrest: an analysis of computer records of security cards that showed Clark was the last person to see Le alive, his failed polygraph and scratches on his body, his attempts to clean up the crime scene and ultimately the DNA match in two places.
Police believe that Le fought for her life.
Investigators found a single bead from a necklace she was wearing in the lab area where she was last seen. They also found tiny blood droplets in that area.
Clark also had scratches and bruises on his arms and back. When he was interviewed by FBI agents, Clark said the scratches were cuts from a cat and from playing softball. The sources said authorities were investigating further into the scratches.
Computer records of his swipe card show he left the building several times and also moved between several rooms, including some that he had no reason to be in, a source said.
Late Tuesday night, police searched Clark's Middletown apartment and collected hair, fingernail and saliva samples from him. Clark cooperated and was released to his attorney.
Sources said that Clark did not give a statement to police. Clark also maintained silence when a bail commissioner tried to interview him before his arraignment Thursday in Superior Court in New Haven.
Judicial marshals led a leg-shackled Clark, who was wearing a striped polo shirt and tan pants, into the courtroom filled with journalists. Neither Le's nor Clark's family members appeared to be in the gallery.
The muscular Clark, a former high school athlete, looked pale and said, "Yes sir," softly when Judge Jon C. Blue asked whether he had been read his rights.
Blue set Clark's bail at $3 million, citing the serious nature of the case.
Investigators are still trying to nail down a motive for the attack, sources said. Those sources said police were looking into whether a work dispute may have sparked the attack on Le, whose body was found Sunday -- the day she was supposed to be married.
The state medical examiner said Le died of traumatic asphyxiation due to neck compression.
ABC News, citing sources, reported Thursday that Clark, an animal laboratory technician, had sent a text message to Le on Sept. 8 -- hours before she was reported missing -- requesting a meeting to discuss the cleanliness of research animals' cages.
The Associated Press, also citing sources, reported Thursday that Clark was described as a "control freak" who often clashed with researchers and viewed the laboratory and its mice as his territory.
New Haven Police Chief James Lewis didn't offer a possible motive for the killing, but said in a news conference what the crime wasn't.
"This is not about urban crime. It's not about university crime. It's not about domestic crime, but an issue of workplace violence," Lewis said.
He said reports that Le and Clark had a romantic relationship are false. He also declined to answer a reporter's question about whether Clark had complained about Le's treatment of animals.
Students and staff who worked at the expansive Yale Animal Resources Center said the building appeared to be very secure.
"It's a fairly isolated place," said Amy Yuan, 21, a student who conducts research in a lab that connects with the one in which Le and Clark worked. "I thought it was the safest place you could be. You need security to get into the building, into the research labs, in the elevator to get into the basement, and swipe again to get into the animal facilities."
Yuan said that when she would spend hours working in the basement's animal facilities on weekends, she rarely saw other people there.
News of Clark's arrest allayed much of the anxiety that had settled over the university after Le's disappearance.