(AP) - Staffers in white coats reportedto work Friday at the end of an extraordinary week at Yale aspolice considered whether a graduate student's grisly death mighthave stemmed from a dispute with an animal research techniciandescribed as an overbearing "control freak." A law enforcement official said police are looking into thepossibility that Raymond Clark III's attitude led to a deadlyworkplace confrontation with 24-year-old Annie Le. She vanishedSept. 8, and her body was found in a utility compartment in a Yalemedical school building five days later, on what was to be herwedding day. Police charged Clark, 24, with murder on Thursday, arresting himat a motel a day after taking hair, fingernail and saliva samplesto compare with evidence from the grisly crime scene. Bond was set at $3 million for Clark, who kept his head down andsaid "Yes, your honor," when asked whether he understood hisrights. He did not enter a plea. The official, who spoke to The Associated Press on condition ofanonymity because the investigation is ongoing and many detailsremain sealed, said Yale workers told police that Clark was a"control freak" who clashed with scientists and their proteges inthe lab where they both worked at the prestigious Ivy Leagueschool. Investigators haven't decided if the theory will ultimately leadto a motive, but don't believe that they'll need to establish onewhen Clark goes to trial because they have an abundance of strongforensic evidence, the official said. Authorities are offering few details about the crime. They wouldnot discuss a motive, largely because Clark will not talk topolice, and would not disclose the DNA test results or how theyconnected Clark to the slaying. Security guards continued their street patrols Friday morningand news crews set up for another day of staking out the college'smedical complex. A makeshift memorial of candles and flowers wasarranged at the entrance to a park across the street from the labbuilding, in an area of squat, utilitarian buildings about a mile from the majestic main campus. Le's work there involved experiments on mice that were part ofresearch into enzymes that could have implications for treatment ofcancer, diabetes and muscular dystrophy, while Clark's technicianjob involved cleaning floors and mouse cages. At a news conference Thursday, New Haven Police Chief JamesLewis called Le's death a case of workplace violence. He would notelaborate except to say reports that the two had a romanticrelationship were untrue. "It is important to note that this is not about urban crime,university crime, domestic crime but an issue of workplaceviolence, which is becoming a growing concern around the country,"Lewis said, adding that he would not rule out additional charges. The Rev. Dennis Smith, a Le family spokesman, said he was notauthorized to comment on the arrest. Smith said he did not knowwhether Le had ever complained about Clark. Clark appeared in court with two public defenders who were newto the case. Public defender Joseph Lopez said he was still reviewing thecase and declined to comment. Two friends of Clark's since childhood, appearing on CNN's LarryKing Live on Thursday night, said they were stunned by the murderallegations and could not reconcile them with the young man they'veknown for years. "That's not the Raymond Clark I've talked to my whole entirelife," Bobby Heslin said. "I just can't picture him doing something like this," MauricePerry said. The New York Times reported that Clark at times grew angry iflab workers did not wear shoe covers. "He would make a big deal ofit, instead of just requesting that they wear them," said aresearcher who asked not to be identified. ABC News reported that Clark sent a text message to Le on theday she vanished requesting a meeting to discuss the cleanliness ofmouse cages in the research lab. The Connecticut medical examiner said Wednesday that Le died of"traumatic asphyxiation," which could indicate a choke hold orsome other form of suffocation caused by a hand or an object suchas a pipe. Investigators focused on Clark early in the investigation andsearched his apartment Tuesday, when they labeled him a person ofinterest. He remained under constant surveillance after he wasreleased early Wednesday and found a room at a motel in Cromwell,Connecticut. Clark was arrested about 8 a.m. Thursday. Details of the warrantremained sealed. Brian Garnett, a spokesman for the Connecticut Department ofCorrection, confirmed that Clark was being held Thursday night atthe MacDougall-Walker Correctional Institution, a high-securityfacility in Suffield, about 20 miles north ofHartford. Garnett said it was unclear whether Clark would remain thereuntil his next scheduled court date Oct. 6. Yale President Richard Levin released a statement shortly afterthe arrest, saying Clark's employment history raised no suspicions. "This incident could have happened in any city, in anyuniversity, or in any workplace. It says more about the dark sideof the human soul than it does about the extent of securitymeasures," Levin said in a message sent to the Yale community.