ST. LOUIS – A St. Louis man is behind bars after he allegedly impersonated a police officer and entered a woman’s apartment without permission while armed.

The St. Louis Circuit Attorney’s Office has charged Ivan Agustin Fierro, 29, with false impersonation of a law enforcement officer and first-degree trespass. Prosecutors formally filed charges on Saturday, per Missouri court records.

According to court documents obtained by FOX 2, on April 2, a suspect later identified as Fierro entered a woman’s apartment on Delor Street. He reportedly entered through an unlocked door, though he was not invited. Once inside, he falsely claimed he was a police officer and looking for someone.

The victim told police that Fierro remained in the apartment for about 10 minutes and observed him in possession of a firearm that was tucked into his waistband. When she told him not to enter without permission, Fierro insisted he was a police officer and could legally enter, adding that he would show her his badge, per court documents.

The victim told police that Fierro appeared to be under the influence of an unknown substance. Court documents did not disclose any prior history between the victim and Fierro before the alleged incident.

Police say Fierro was arrested Friday with ammunition in plain view. After his arrest, the victim was able to positively identify him.

Fierro was booked into jail without bond, per Missouri court records. As of Saturday, no court dates have been scheduled.