A man opened fire on officers during a domestic disturbance call Saturday morning, killing three of them, a police official said.
Friends said 23 year-old Richard Poplawski feared the Obama administration was poised to ban guns.
Three officers were killed.
Police planned to release more details at a 3 p.m. news conference Saturday.
Poplawski was arrested after a several-hour standoff.
One witness reported hearing hundreds of shots.
The shootings occurred just two weeks after four police officers were fatally shot March 21 in Oakland, Calif., in the deadliest day for U.S. law enforcement since Sept. 11, 2001.
Poplawski's friends at the scene described him as a young man who thought the Obama administration would ban guns.
One friend, Edward Perkovic, said Poplawski feared "the Obama gun ban that's on the way" and "didn't like our rights being infringed upon."
