Montgomery County police are investigating the slaying of a 40-year-old Suburban Hospital employee, an incident which prompted a four-hour lockdown Saturday at the medical center's Bethesda campus. Police received a report of the assault at the hospital at 10:29 a.m., Montgomery County police spokeswoman Lucille Baur said.

Officers found a man suffering from trauma to the upper body, and preliminary information indicated he may have been stabbed, Baur said.

Baur said the man was pronounced dead at the scene of the attack, which took place in an area that was not occupied by patients. Police and hospital officials would not elaborate on the nature of the man's injuries though Baur said detectives are investigating the death as a homicide.

The hospital, which is located at 8600 Old Georgetown Road, was placed on lockdown from 10:30 a.m. until 2:30 p.m. while police searched for the killer. Incoming patients were diverted to another hospital, and no one was allowed to enter or leave the building, Suburban spokeswoman Susan Laine said.

Police determined that the suspect was no longer in the hospital, and Baur said officers don't have information on where the killer might have gone. Baur could not say whether the victim knew his attacker or if more than one person was involved.

The victim's name was not released because his family was still being notified. His remains were sent to the Office of the Chief Medical Examiner in Baltimore for autopsy.

Baur would not say whether there were any witnesses to the assault or whether the attack was recorded on video surveillance.

No one else was injured in the incident.

Laine said the hospital's staff was "alerted and appraised of the situation" as it occurred.

The hospital also posted messages for staff and the public on Facebook and Twitter pages. Employees were instructed to report for work during the lockdown, and police checked identification before staff was allowed to enter the hospital.