Boston police and a cadre of federal officials descended on an Ocean Avenue apartment complex in Revere last night.

In addition to two Boston Police K-9 units and a bomb squad unit, a large contingent of federal agents from the FBI, Immigration and Customs Enforcement, as well as Homeland Security investigations and state police had assembled at the two buildings.

It was unclear whether the search was connected to the Boston Marathon bombings. Tight-lipped agents said nothing to assembled media. Worried building residents said they were left in the dark.

Marcus Worthington, 24, a building resident said no one has told him what was happening.

“I started noticing the cars, the Taurus there and that one about 5,” Worthington said. “We were thankful we decide not to go down. It’s best not to jump to conclusions.”

Worthington’s girlfriend Whitney Drake, 24, was concerned.

“It’s never a good thing to see all of these agencies. It’s more than a local problem,” Drake said.

Revere Fire Department engine and ladder arrived with Cataldo Ambulance service arrived about 10:30 p.m.

Officials had no comment when asked by reporters what was happening.

Boston Police Crime Scene Response unit which collects evidence following major crimes arrived and two members of that unit took several brown paper bags, normally used to store evidence taken from the scene, into the building.