Authorities in Wisconsin say a 26-year-old man is facing charges related to the shooting death of a Milwaukee police officer last week.

According to Fox News, Jordan P. Fricke was arrested following the homicide of 35-year-old Matthew Rittner, who was at the suspect’s home on Wednesday morning as part of a team attempting to serve a search warrant for prior drug- and weapons-related counts.

While police reports show police made their presence known loud and clear, Fricke reportedly told investigators that he did not know police were outside when a commotion woke him and his girlfriend up that morning.

A criminal complaint claims he believed someone said “police” during the incident, but he did not believe the intruders were legitimate officers and never heard them announce they had a search warrant.

His girlfriend reportedly told police that she heard the officers identify themselves and saw Fricke walk to the door and shoot through it.

Fricke was allegedly armed with an AK-47 semiautomatic pistol, as reported by the Milwaukee Journal Sentinel,

He allegedly fired his weapon four times through the hole a police battering ram left in the door, fatally striking Rittner in the chest. A funeral for the officer, who joined the agency 17 years ago, is scheduled for Wednesday in Oak Creek.

Fricke was arrested on Sunday and booked into jail with bail set at $500,000. He is expected to face criminal charges including intentional homicide in the first degree. In addition to other counts related to the incident on Wednesday, he is facing the earlier charges of reckless endangerment and drug offenses.

[Featured image: Jordan Fricke, Milwaukee County Jail]