A federal probe into possible misconduct within the Lawrence Police Department has stalled as the FBI waits for a formal complaint to be filed.

FBI spokesman Jeff Lanza said no one had come forward with a formal complaint alleging anyone posed as FBI agents when questioning people in relation to a police investigation of an alleged fencing ring at the Yellow House secondhand shop, 1904 Mass.

“We cannot move forward without a formal complaint,” Lanza said.

Lanza previously said the FBI was looking into the matter.

Sarah Swain, attorney for Yellow House, said she and a private investigator were working to set up a meeting between the FBI and people who allegedly have been interrogated by police officers claiming to be federal agents.

Swain also said a private investigator sent the FBI at least one sworn affidavit that should serve as a formal complaint.

The Lawrence Police fencing investigation, which began last year, has focused on the alleged purchase and resale of stolen goods through the secondhand store and online sales, according to a police news release from December 2005.

Police have served search warrants at the Yellow House and at the home of Guy and Carrie Neighbors, the store owners, in relation to the case.

No charges have been filed as a result of the monthslong fencing investigation.

The police department has declined comment about the FBI inquiry, saying it was against department policy to discuss another agency’s probe.