A Lab technician was arrested early on Thursday and charged in the killing of Annie M Le, a Yale graduate student whose body was hidden in the wall of a university building after she was strangled, the police in New Haven said.

The technician, Raymond Clark III, 24, was taken into custody at a Super 8 motel in Cromwell, Connecticut, after DNA evidence linked him to Le’s killing, the police said. He did not resist. Chief James Lewis of the New Haven police would not provide a motive when he announced the arrest, but he emphasised that the authorities believed it was a workplace crime.

“It is important to note that this is not about urban crime, university crime, domestic crime, but an issue of workplace violence, which is becoming a growing concern around the country,” he said. Clark was arraigned in New Haven Superior Court. Judge Jon C Blue set bail at $3 million because, he said, it was “obviously a very serious case”.

In response to the judge’s confirming that he had read Clark his rights, Clark simply nodded and said, “Yes, Sir.” He did not enter a plea, and his next court appearance will be on October 6.