Federal agents searched a Spokane apartment Saturday morning in connection with ricin-laced letters intercepted last week at a Spokane post office processing facility.

Neighbors woke up to the sound of doors slamming as Spokane police officers blocked off streets in Browne’s Addition. Federal agents wearing gas masks stormed the second floor of the Osmun Apartments along First Avenue near Oak Street about 7 a.m.

“I heard banging and what sounded like a scuffle,” neighbor Scott Ward said. “I thought somebody was getting hurt.”

He opened his door and saw a SWAT team. They told him to get back inside and lock his door.

FBI spokeswoman Ayn Sandalo Dietrich said that no arrests had been made as of late Saturday.

She declined to say whether a suspect had been identified. Authorities were withholding details, she said, because they were in the middle of their investigation.

Neighbors in the apartment building were allowed to remain inside their units and to come and go from the property, but First Avenue was cordoned off with police tape from Oak to Elm streets.

The FBI, the U.S. Postal Inspection Service and Spokane police took part in the operation. Some agents wore hazardous materials gear to protect against possible contamination from ricin, a deadly poison. The search was related to ricin-laced letters – one addressed to a federal judge and another to the Spokane post office – that were postmarked Tuesday, officials said.

“There is no public risk,” Sandalo Dietrich said.

A group of neighbors in the middle of moving had to haul items an extra half-block to a moving truck, which was not allowed inside the police work area.

A postal worker delivering mail in the neighborhood adjacent to the search walked up to one of the U.S. postal inspectors and congratulated him for what appeared to be a break in the case.

The search continued through the evening. Police Chief Frank Straub was among the officers working on the case.

The FBI said earlier this week that the letters were seized during routine screening at a postal processing facility in Spokane but provided no other details.

Ricin is a poison derived from the castor bean plant.

Postal management told postal worker union members that they had no reason to believe any employees were at risk from handling the suspect letters as they passed through the mail stream in Spokane.

The Postal Service said preliminary tests on the letters showed the presence of ricin, but the substance was in a form that could not easily be inhaled or ingested.