"It's all up to the lab now," Police Chief James Lewis said at a news conference. "The basis of the investigation now is really on the physical evidence."
Police served two search warrants -- for DNA from Clark and for items in his apartment -- late Tuesday. They served two more Wednesday morning, for more items from the apartment and for Clark's Ford Mustang, Lewis said.
Investigators said they expect to determine within days whether Clark should be charged in the killing. He was escorted in handcuffs from his apartment and released early Wednesday into the custody of his attorney, police said.
Lewis said Clark and several other people are under constant police surveillance. He said police expect to seek an arrest warrant for anyone whose DNA matches evidence at the crime scene.
Clark is not talking to police, Lewis said.
"At some point he may be willing to answer questions, but at this point he has invoked his rights," Lewis said. "He has an attorney. We couldn't question him if we wanted to."
Clark's attorney, David Dworski, said his client is "committed to proceeding appropriately with the authorities." He would not elaborate.
A police lab is expediting tests on Clark's DNA. University of Connecticut genetics professor Linda Straus Baugh says testing can be done in days if a case gets top priority.
Clark's job as an animal-services technician at Yale put him in contact with Le, who worked for a Yale laboratory that conducted experiments on mice. She was part of a research team headed by her faculty adviser, Anton Bennett, that focused on enzyme research that could have implications in cancer, diabetes and muscular dystrophy. Members of the team have declined to comment on the case or their work.
Clark, his fiancee, his sister and his brother-in-law all work for Yale as animal lab technicians.
Le's body was found Sunday stuffed behind the wall of the basement where lab animals are kept. The Connecticut state medical examiner said Wednesday that Le died of "traumatic asphyxiation."
Authorities released no details on how she died, but traumatic asphyxiation could be consistent with a choke hold or some other form of pressure-induced asphyxiation caused by a hand or an object, such as a pipe.
Clark and Le were both 24 years old, but Clark has a muscular build that contrasts sharply to Le's 4-foot-11, 90-pound frame. Clark also reportedly had a troubling brush with the law in high school after being accused of harassing a girlfriend.
Until recently, Clark's family lived in nearby Branford, a small middle-class suburb of New Haven. In September 2003, when he was a senior at Branford High School, Clark reportedly upset a girlfriend so much that police warned him to stay away from her.
The New Haven Independent reported that when the girl tried to break up with Clark, he attempted to confront her and wrote on her locker.
The girlfriend and her mother told a detective that she had been in a sexual relationship with Clark and that he once forced her to have sex. The relationship continued after that incident, according to the Independent, a news Web site.
The young woman did not pursue the case, and no charges were filed. The Independent reported that Clark was warned in 2003 that police could pursue criminal charges against him if he contacted the girl.
Branford Police Lt. Geoffrey Morgan told The Associated Press on Wednesday that his department would not release the unsubstantiated 2003 report. Morgan would neither confirm nor deny the news report, citing cooperation with police investigating the killing.
Clark played baseball at Branford High School, where longtime athletic director Artie Roy remembered him as a quiet student who threw a mean knuckleball.
"He was a seriously good pitcher and a good infielder," Roy said. "He wasn't a typical off-the-wall knucklehead kind of kid who bounced all over the place," he said. Clark also participated in clubs that raised money for charity and the Asian Awareness group, according to the school's 2004 yearbook, the Milestone.
On her MySpace page, Clark's fiancee, Jennifer Hromadka, calls Clark was a "wonderful boyfriend." She added that she's not perfect, but cautioned people not to judge her.
"Who are you to judge the life I live? I know I'm not perfect and I don't live to be, but before you start pointing fingers make sure your hands are clean!!" the 23-year-old wrote.
The date of the MySpace posting is unclear. The page has since been taken down.
Police are not commenting on a possible motive.
As a technician at Yale, Clark helped clean the cages of research animals used by labs around the Ivy League campus and had other janitorial duties, police said. The technicians help tend to rodents, mostly mice, used in experiments and can help with paperwork.
Since researchers generally try not to move animals from their housing for testing, students and faculty conducting experiments often visit the building where Le was found dead, school officials said.
The Le case has some parallels to the 1998 murder of 21-year-old Suzanne Jovin about 2 miles from the Yale campus. The slaying is still unsolved.
In that case, a professor was named as a suspect early in the investigation and was later fired. He was never charged, and authorities never presented evidence against him.
Without mentioning Jovin's name, Lewis referred to the case Wednesday while defending his department's handling of Le's death.
"We don't want to be in the future accused of tunnel vision and saying that we focused on one person and only one person," Lewis said.
Noting that "tragedy has again struck Yale," Jovin's parents released a letter to Gov. Jodi Rell pleading for more funds for the state's forensic science lab. Thomas and Donna J. Jovin said they share the agony of Le's loved ones.
"We hope that the person guilty of this terrible crime can be apprehended quickly," they wrote, "which was unfortunately not to be true in the case of our daughter."
QUICK HEADLINES | MORE US/WORLD | GET NEWS ALERTS
-----------------------------------------------------------------------------------------------
ABC13 SOCIAL NETWORKING
Find us on Facebook® | Follow us on Twitter | More social networking
-----------------------------------------------------------------------------------------------
MORE FROM ABC13
ABC13 widget | Most popular stories |
Street-level weather
ABC13 wireless |
Slideshow archive |
Help solve crimes
-----------------------------------------------------------------------------------------------
