early Wednesday as part of an "ongoing violent crime" investigation, said Beth Anne Steele, a spokeswoman for the agency.

The warrants were served at 4820 N.E. 31st Ave., 7129 N.E. Eighth Ave., and 6846 N. Greenwich.

No arrests were made.

"The warrants are sealed, and I anticipate they will remain sealed," Steele said.

Some residents in the area of Northeast Alberta Street awakened to the sound of a helicopter circling overhead.

The home at Northeast 31st Avenue, a block from Alberta, is a two-story purple home with purple trim. It was raided around 6 a.m., FBI agents were still at the location as of 10:15 a.m.

Rosa Aguilar, who owns the home and rents it out, said she believed that agents were not looking for the current tenants but a group that moved out more than a year ago. Aguilar said she did not renew the group's lease because she had received so many complaints about them.

FBI raids homes in north and northeast Portland 14 Gallery: FBI raids homes in north and northeast Portland

Puanani Leal, who has lived in the neighborhood three years, described the former tenants as "anarchists" who ran an information booth at Alberta Street's Last Thursday event. She said large numbers of people were in and out of the house while the group was living there.

She was home when the FBI arrived this morning.

"I just heard lots of pounding at 6 o'clock, and I got up and I saw the whole thing," Leal said. "I saw them screaming to get in. They were using the battering ram, and then finally the door just opened."

She said the current occupants came out and agents very quickly let them go.

Near the 7129 N.E. Eighth Ave., home neighbors said no one has lived in the house for several years. In recent months, neighbors noticed activity -- a light on inside, groups of people in their early 20s coming and going. They didn't cause any trouble but seemed to be living in the house.

Then, a month ago, an officer in a patrol car was seen checking out the home.

Neighbors said they heard multiple loud bangs around 6 a.m. this morning, followed by yelling.

By 10:30 a.m., the FBI had left. The rundown home appeared to be empty but for a chair and a desk and a roll of paper towels visible from a window. The grass was overgrown, but the grass in a side yard looked trampled down.

At the location on North Greenwich, the FBI was finishing up processing evidence around 11 a.m. At the one-story blue gray home, agents carted out paper evidence bags sealed in red tape.

Agents examined yard debris. They took pictures inside the house and photographed a white van parked in the driveway.