NEW HAVEN - (AP) - Police were awaiting the results of DNAtests on evidence taken from a Yale University animal researchtechnician before determining whether to charge him with killing agraduate student who worked in the same lab. On Wednesday, the medical examiner reported that Annie Le, whosebody was found stuffed in the wall of a university research center,had been suffocated. Police call Raymond Clark III a "person ofinterest" in the slaying, and they scheduled a news conferenceThursday morning to announce developments in their investigation. Officer Joe Avery, a New Haven police spokesman, told TheAssociated Press early Thursday that Clark was not in custody andpolice did not have a warrant for his arrest. Police in Cromwell late Wednesday were watching a hotel roomwhere a "person of interest" in the killing had been staying,Capt. Roy Nelson said. Broadcast reports said Clark was staying atthe hotel. Police in marked and unmarked cruisers kept a steadywatch near the hotel off a highway, while a crowd of reportersgathered across the street early Thursday. Authorities hoped to compare DNA taken from Clark's hair,fingernails and saliva with more than 250 pieces of evidencecollected at the crime scene on the Ivy League campus in New Haven,Conn., and from Clark's Middletown, Conn., apartment. "It's all up to the lab now," New Haven Police Chief JamesLewis said at a news conference Wednesday. "The basis of theinvestigation now is really on the physical evidence." Clark is not talking to police, Lewis said. "At some point he may be willing to answer questions, but atthis point he has invoked his rights," Lewis said. "He has anattorney. We couldn't question him if we wanted to." Clark's attorney, David Dworski, said his client is "committedto proceeding appropriately with the authorities." He would notelaborate. Police executed two search warrants - for DNA from Clark and foritems in his apartment - late Tuesday. They served two moreWednesday morning, for more items from the apartment and forClark's Ford Mustang, Lewis said. Investigators said they expect to determine within days whetherClark should be charged in the killing. He was escorted inhandcuffs from his apartment and released early Wednesday into thecustody of his attorney, police said. Lewis said police expect to seek an arrest warrant for anyonewhose DNA matches evidence at the crime scene. A police lab is expediting tests on Clark's DNA. University ofConnecticut genetics professor Linda Strausbaugh says testing canbe done in days if a case gets top priority. Clark's job as an animal-services technician at Yale put him incontact with Le, who worked for a Yale laboratory that conductedexperiments on mice. She was part of a research team headed by herfaculty adviser, Anton Bennett, that focused on enzyme researchthat could have implications in cancer, diabetes and musculardystrophy. Members of the team have declined to comment on the caseor their work. Clark, his fiancee, his sister and his brother-in-law all workfor Yale as animal lab technicians. Le's body was found stuffed behind the wall of the basementwhere lab animals are kept. The Connecticut state medical examinersaid Wednesday that Le died of "traumatic asphyxiation." Authorities found her body Sunday, the day she was to bemarried, but released no details on how Le died. Traumaticasphyxiation could be consistent with a choke hold or some otherform of pressure-induced asphyxiation caused by a hand or anobject, such as a pipe. Police are not commenting on a possible motive. As a technician at Yale, Clark helped clean the cages ofresearch animals used by labs around the Ivy League campus and hadother janitorial duties, police said. The technicians help tend torodents, mostly mice, used in experiments and can help withpaperwork. Since researchers generally try not to move animals from theirhousing for testing, students and faculty conducting experimentsoften visit the building where Le was found dead, school officialssaid.