(CNN) -- Violent incidents early Friday, including the shooting death of a college police officer, kept Bostonians on edge just days after the bombing of the iconic Boston Marathon.
Howling sirens pierced the night quiet, and flashing lights lit up the darkness, as dozens of officers from state and city police responded to the deadly shooting on the campus of the Massachusetts Institute of Technology in Cambridge. Hardly an hour later, they were chasing suspects in a hijacked vehicle just less than five miles away.
There were reports that explosives may have been involved before police cornered the vehicle.
"Police were in a standoff with the vehicle just down the hill," said CNN photographer Gabe Ramirez saw the chase end in Watertown. They ordered the suspect out of vehicle and commanded he strip down naked before putting him in a patrol car and transporting him away from the scene, Ramirez said.
Police ran down the streets of Watertown, according to CNN affiliate WCVB, which broadcast images from the pursuit. One man could be seen lying face down on the street in a surrender pose with his hands outstretched in front of him and his legs crossed.
Dozens of police from various units arrived in Watertown, some in SWAT uniforms, others wearing helmets. Large crowds gathered around a trove of emergency vehicles that had congregated in the neighborhood, WCVB reported.
But even with all this activity it was unclear if the arrest in Watertown was related to the shooting on the MIT campus or any other incident in the Boston area.
How it began
The nightly mayhem began, after a university police officer died in a shooting on the Massachusetts Institute of Technology campus in Cambridge late Thursday, state police spokesman Lt. Mark Riley said.
The MIT officer was responding to a disturbance when he was fired upon, according to the state district attorney's office. He sustained "multiple gunshot wounds."
State police and the FBI were called in after the shooting and found the campus policeman near Building 32 on MIT's campus. He was taken to Massachusetts General Hospital, where he was pronounced dead, the district attorney's office said.
Dozens of officers surrounded and cordoned off the building, known as the Stata Center, which houses computer science laboratories as well as the department of linguistics and philosophy, according to MIT's website.
The university, which lies adjacent to the city of Boston, requested people stay away from the building as police considered the situation potentially dangerous.
Students and faculty received e-mails to alert them to the event, CNN affiliate WCVB reported.
Residents in the area have been on edge after two bombs ripped through the crowd near the finish line of the Boston Marathon, killing three people and injuring about 180 others. Police are seeking two suspects in the attack, and they are still at large.
Many news media outlets are in the area covering the investigation into Monday's bombings and arrived at MIT to cover the shooting, WCVB reported.
The Stata Center also contains a food court, WCVB said. It serves as a gathering area for students.