BROOKFIELD, Wisconsin: A gunman burst into a day spa where his estranged wife worked in the midwestern US state of Wiscon-sin and opened fire on Sunday (Monday in Manila), killing three people and injuring four others, police said.

The suspect, identified as 45-year-old Radcliffe Haughton, was later found dead at the scene in Brookfield, a suburb of the city of Milwaukee, police told Agence France-Presse.

Haughton died from a self-inflicted gunshot wound, Brookfield police chief Dan Tushaus said.

“We believe this incident is domestic violence-related,” he told reporters, noting that officers discovered a small fire inside the building when they went in for the suspect and found him dead.

Women who were trying to relax by getting massages and nail treatments instead ran for their lives when the gunman entered the Azana spa, police said.

Clients stood dumbfounded in the parking lot in their white spa robes outside the locked-down crime scene, as police spent hours combing the large building, which had many small treat-ment rooms.

Police said that Haughton’s wife apparently wanted a divorce and he had slashed her car tires earlier this month, prompting her to take out a restraining order against him, Tushaus said.

But it did not stop Haugh-ton from targeting her work-place, police admitted. They said that they could not immediately say if his wife was among the dead.

The suspect’s father, Radcliffe Haughton Sr., told TMJ4 News: “This is not the way I raised my son . . . My son is facing a domestic problem. Things happen, and some people cannot take it.”

Sunday’s mass shooting was the second in the US state this year. In August, six people were killed in a rampage at a Sikh temple in another suburb of Milwaukee, Oak Creek. The gunman in that incident killed himself.

Tushaus said earlier that Haughton had left behind what appeared to be an improvised explosive device (IED), which prevented police from searching the entire two-story building.

But the police chief later said that it was unclear if the propane tank was an IED or something left behind by maintenance or construction workers.

The four people injured in Sunday’s shooting were not believed to be critically hurt. However, one woman who was shot in the neck may be about six months pregnant, TMJ4 reported.

Police would not immediately identify the dead, other than the shooter himself. They were not looking for any other gunmen, Tushaus said.