Chief John Downs of the Hyattsville Police Department was relieved of all duties by the City Council's safety committee this week pending an investigation into allegations of official misconduct, Hyattsville officials said yesterday.

Downs was placed on administrative leave with pay.

City officials refused to comment on the suspension, and Downs, who came to the Hyattsville department in 1971 after serving about 10 years on the University of Maryland Police Department, denied being involved in any misconduct. Downs referred a reporter to his attorney, but the attorney is on vacation and could not be reached for comment.

City Attorney Lance Billingsley said, "This is just an investigation. There must be presumption that the police chief has not been involved in any wrongdoing."

Billingsley said the investigation should be completed in two weeks and compared the administrative leave to the routine suspension by Prince George's County of county policemen who fire weapons in the line of duty.

He said the city is following a personnel procedure set down by a state law - the so-called policemen's bill of rights - and that Downs has been advised of the complaints against him.

Downs has been temporarily replaced as head of the 30-member police force by Lt. Charles Arnett, who referred all questions about Downs to the city administrator. Robert T. Johnson, who also refused comment on the investigation.

Hyattsville Mayor George C. Marrison says that by law Johnson is responsible for investigating the complaints against the chief.