Updated

Republican U.S. Rep. Marilyn Musgrave's re-election campaign was already heated, and it just got smelly as well: Her staff accused a Democratic activist of leaving an envelope full of dog feces at her office here.

Someone stuffed the envelope through the mail slot in the door on May 31 and then sped away in a car, Musgrave spokesman Shaun Kenney said. He said most of the preprinted return address was blacked out, but staffers used the nine-digit ZIP code to trace it to Kathleen Ensz, a Democratic volunteer.

Ensz told The Associated Press she left the envelope at Musgrave's office but said it "wasn't in the office doors, it was in the foyer." Asked what she meant by the act, she declined comment.

Kenney demanded an apology from Musgrave's likely Democratic opponent, state Rep. Angela Paccione of Fort Collins.

Paccione spokesman James Thompson said Ensz has no formal ties to the Paccione campaign.

Greeley Police Sgt. Joe Tymkowych said Ensz had been cited for criminal use of a noxious substance. She is due in court Aug. 10.