An MIT police officer, whose name has not been released, was shot dead Thursday night, local time. According to the local county district attorney, the victim was shot several times and was pronounced dead at the hospital.

Local and state investigators began a search for the gunman soon afterwards.

The prestigious university, home to some 11,000 students in the US city of Cambridge, remained on lock down several hours after the incident.

Several hours after the shooting, MIT officials lifted the lockdown, but advised students to "remain vigilant in the coming hours," according to a statement posted on the university's official website.

"MIT Police have determined that the suspect in this evening's shooting is no longer on campus," the statement said.

A spokesperson from the district attorney's office said authorities doubted the shooting had a connection to two deadly explosions that left three dead and over 170 wounded at the Boston Marathon earlier this week.

However, none of the investigators could dismiss the possibility "with 100 percent certainty at this time," Middlesex County District Attorney's office spokesperson David Procopio told the news agency Reuters.

MIT is located in Cambridge, Massachusetts, across the Charles River from Boston.

While the motive behind the Boston Marathon bombings remains unknown, FBI officials were able to release photos of two suspects late Thursday in what they hoped would lead to a turning point in the terror case.

kms/ipj (AFP, Reuters)