A police officer and three other people were killed in a series of shootings Wednesday in northern Wisconsin that apparently began as a domestic dispute in a bank, officials said.

Everest Metro Police Chief Wally Sparks said at a news conference the slain officer was from his department and that a suspect was in custody. Sparks did not release the officer's name or the names of the other three dead.

Authorities took no questions in a brief news conference, but said there was no remaining threat to the public.

We're at a standoff in Marathon County where more law enforcement just arrived for ongoing situation. Police not providing many details. pic.twitter.com/Z3i3lwOamW — Ben Krumholz WLUK (@BenKrumholzWLUK) March 22, 2017

"I would like to send all my thoughts and ask everybody listening, Thoughts and prayers to all the victims and their families.'" Sparks said. "Please keep them in your prayers and be with our officers."

Jason Smith, a deputy administrator for the state Department of Justice's Division of Criminal Investigation, said more than 100 officers were investigating and more information would be released Thursday.

The shootings happened at a bank, a law firm and an apartment complex, where officers, including a SWAT team, had a standoff with the suspect for several hours before ending in a volley of gunfire around 5 p.m., police said.

A woman who lives in the complex told the Associated Press she looked out her apartment window in the small town of Weston about 1:15 p.m. to see a squad car approach, and a few seconds later heard a gunshot and saw the officer fall. Kelly Hanson, 21, said she saw other officers put the wounded policeman in an armored SWAT vehicle and take him away.

"I thought, what is going on? I know what a gun sounds like, and thought 'This isn't good,'" Hanson said. Hanson said she stayed in her apartment until about 4:45 p.m. when she heard a volley of about 10 shots and began to "freak out." Authorities eventually let her leave her apartment.

"It's tragic that had to happen, but I think they did a good job out here today," she told the AP.

Dozens of police cars and emergency vehicles responded after the first shooting happened around 12:30 p.m. at Marathon Savings Bank in Rothschild. Officers responding to a reported domestic situation arrived to find two people had been shot.

A second call then came about 10 minutes later from the Tlusty, Kennedy and Dirks law firm in nearby Schofield, and then a third report came in at 1:30 p.m. from an apartment complex in Weston.

SWAT members entered the apartment building about 2:30 p.m., the Wausau Daily Herald reported. Nearby schools and a hospital went on lockdown. The lockdowns were later lifted.

Susan Thompson, a resident of the building, told the newspaper she heard gunshots and heard someone scream. As she left her apartment, police called to her to get inside and lock her doors. Thompson, 21, said she had her 2-year-old daughter in the apartment. Officers later came to her door and helped her and her daughter outside, she said.

Omar Sey, 31, who said he had just moved to the apartment complex, learned of the shooting after he arrived home to find dozens of squad cars outside. Sey, who said he had moved to Wisconsin from Gambia, said he didn't understand why such things happen in America.

"This is crazy," he said. "You have everything at your disposal. Why don't you make your life better instead of engaging in this."

The Associated Press contributed to this report.

Read more from FOX11Online.com.