A psychiatric patient was shot dead by an off-duty security guard after stabbing his doctor at a Massachusetts General Hospital facility Tuesday afternoon, police said, marking the third attack in a Boston hospital since last Thursday.

Boston Police Department spokesman Sgt. Eddy Crispin said police identified Jay Carciero, 37, of Reading as the attacker. The stabbing victim is in stable condition and is expected to live, Crispin said.

The stabbing occurred around 2 p.m. at 50 Staniford Street in Boston, an office building where the hospital’s Bipolar Clinic and Research Program is located.

‘What we know at this point is that apparently the suspect was stabbing a medical doctor who was working at the building,’ Crispin said. ‘The security guard ordered the patient to drop his knife, he didn’t, and the security guard shot him.’

BPD has not released the names of the doctor and the security guard. However, a relative of the doctor told The Boston Globe the victim was Dr. Astrid Desrosiers, a MGH psychiatrist who worked at the center.

Crispin said the case is still under investigation. The attacker’s motivation remains unclear, he said.

This was the second attack at the MGH in a week. A 27-year-old female worker was assaulted inside a restroom by a homeless man Thursday afternoon, according to an Oct. 27 article in The Boston Globe. David Flavell, 40, a repeat sex offender, was identified as the attacker and ordered Tuesday to go through a mental competency evaluation at Bridgewater State Hospital, the Globe reported.

A 38-year-old man was also badly hurt in a stabbing Sunday at Boston Medical Center, officials said. The victim, whose name has not been released, was stabbed in the neck. His attacker is still at large.

Staff reporter Jenny Roche contributed to the reporting of this article.