The Waukesha County District Attorney's Office is investigating a fatal officer-involved shooting near Prairie Park in the early hours of Sunday morning.
According to a release by Waukesha Police Department, around 12:30 a.m. officers were in the area of School Drive and Prairie Avenue pursuing a suspect accused of involvement in a forgery case.
Police say the suspect has past convictions that include theft, fraud and battery to a peace officer.
Upon locating the suspect, police say the man pulled out a knife and threatened and charged at the officer despite the officer's attempts to diffuse the situation and verbal commands.
The officer shot the 55-year-old suspect, striking him four times in the chest.
Two back up officers arrived at the scene and all three assisted in stabilizing the man and rendering aid, officials said.
Waukesha Fire Department transported the suspect to Waukesha Memorial Hospital where he later died.
Waukesha Police have not yet released the name of the suspect or officer.
The involved officer has over five years of experience has been placed on administrative leave.
The investigation will be led by the Milwaukee Area Investigative team.