Police search for armed carjackers near BU Bridge

State and local police launched a two-hour manhunt for two armed carjacking suspects, who remained at large as of last night, around the site of the alleged crime at the BU Bridge and Memorial Drive in Cambridge yesterday.

At 5:07 p.m., the suspects – described as black males, one wearing a white shirt and the other a black shirt – jumped into the back of a 2007 Nissan Maxima as the driver and passenger waited at the Allston-Brighton Tollbooth at Interchange 19 on the Massachusetts Turnpike, said Barry O’Brien, spokesman for the Massachusetts State Police.

One of the suspects pistol whipped the passenger before arriving at the tollbooth, O’Brien said. When the black car pulled up, the passengers were able to alert the attendant that they were in danger, he said. The worker immediately alerted a state trooper.

Shortly after passing through the tollbooth, the Nissan sideswiped another vehicle and halted, and the suspects ran toward the railroad tracks underneath the BU Bridge, O’Brien said.

State police arrived beneath the bridge at 5:30 p.m., followed by police from Boston University, the Massachusetts Institute of Technology, Cambridge and Boston. MBTA police arrived because the search blocked transportation on the Worcester-Framingham commuter rail.

Helicopters, Marines and a canine unit joined the search in the dense foliage on the Cambridge side of the BU Bridge, near the Hyatt Regency hotel.

Police stopped looking at 7:15 p.m., after they sent two canine units into the area followed by officers who drew their weapons. The helicopter circled the scene until the sky began to darken.

“I don’t know . . . if [the search is] still going on, but I would surmise that after a certain amount of time [the police] are going to check out other investigative avenues to find the suspects,” O’Brien said late last night.

Matt Negrin contributed reporting for this article.