DETROIT — A prosecutor yesterday accused Mayor Kwame Kilpatrick of violating his bond in an assault case by spending time over the weekend with his sister, one of 11 witnesses listed by authorities.

Mr. Kilpatrick and Ayanna Kilpatrick were together at their mother’s house Saturday, a day after he was released from jail for violating bond in a separate perjury case, Doug Baker of the Michigan attorney general’s office said.

The mayor is charged with assaulting two investigators who were trying to deliver a subpoena at his sister’s house in July in the perjury case.

In a court filing, Mr. Baker said the mayor had been ordered to have no contact with witnesses.

Mr. Kilpatrick’s defense team, however, believes the mayor is not in trouble. Attorney Jim Thomas said Magistrate Renee McDuffee clarified Friday that Mr. Kilpatrick could have contact with his sister.

In a statement, Mr. Kilpatrick spokesman, Marcus Reese, accused state Attorney General Mike Cox, a Republican, of trying to score political points with the latest filing against the embattled Democratic mayor.

District Judge Ronald Giles will hold a hearing on the matter on today.

Judge Giles is the judge who sent Mr. Kilpatrick to jail Thursday for violating his bond conditions in a perjury case involving Mr. Kilpatrick and a former top aide. The mayor traveled to Windsor, Ontario, for city business July 23 without first notifying authorities.

Mr. Baker’s filing asked the court to look at what happened and amend the terms of Mr. Kilpatrick’s bond. The document doesn’t mention any possible changes, and Mr. Baker left court without speaking to reporters.