The park where the shooting took place is one of the most visible areas of the city with workers frequenting a Starbucks there, children skating at the ice rink and, in warmer weather, teens and young adults gathering to ride unicycles. The park also is across the street from the historic City Hall building downtown, and many people inside heard the shots, including Bill Arnold, the public information manager for the city of Milwaukee.
Arnold said he was on the other side of the building on the third floor when he heard six to eight shots in "quick succession" and walked to the north side to see what happened. He had little doubt they were gunshots.
"We made that determination quickly because of the way the sound reverberated and the quickness of the sounds all in a row: bam, bam, bam, bam," he said.
He looked outside and saw police officers and first responders doing chest compressions on the suspect.
Police Chief Ed Flynn said the beat officer in that neighborhood had gone to the park after receiving a call about a man who was lying on the ground. When the officer arrived, he helped the man to his feet and then started to check him for weapons.
"A struggle ensued. The officer withdrew his baton, and it is our understanding that he began to defend himself, at which time, the subject took it from him," Flynn said. "The subject began to beat the officer with the wooden baton, striking him in the head."
The 38-year-old officer drew his gun and fired at the suspect several times, killing him, the chief said.
Alderman Robert Bauman told the Milwaukee Journal Sentinel he heard shots and looked out the window of his second-floor office to see the officer fire his weapon and then drop to one knee.
"The victim was faltering and stumbling. I saw the officer on the radio. There was about a two-minute lag and then the cavalry arrived," Bauman said.
About 30 officers converged on the park, bringing ambulances and other emergency workers. The officer, a 13-year police veteran, was taken to a hospital with head injuries, Flynn said.
The chief said the suspect had not been identified and remained on the ground with the baton underneath him as officials spoke to reporters across the street.
The shooting is the first in the city since a state law went into effect Friday requiring an outside investigator to run officer-involved death investigations. Flynn said the state Department of Investigation will lead the inquiry, with help from the district attorney's office and other agencies.
Flynn said officers were canvassing downtown businesses and homes to find witnesses and seek surveillance video.
Milwaukee Mayor Tom Barrett, who heard five to eight gun shots while in a meeting on the sixth floor, said there was no lockdown at City Hall.
"I want the people of this community to know this is a rare and isolated incident in downtown Milwaukee," Barrett said. "Downtown Milwaukee is extremely, extremely safe."
Associated Press writers M.L. Johnson and Carrie Antlfinger contributed to this report.