According to police, a Bay Area father shot and killed four people, including his wife, six-year-old son and in-laws

ALAMEDA, California – A San Francisco Bay Area man is in custody after shooting his wife, their 6-year-old son and his wife’s parents, authorities said Thursday.

A second son, 1 year old, was also shot and is in critical condition in the hospital, Alameda Police Chief Nishant Joshi said at a news conference Thursday.

Officers arrived at a residence on Kitty Hawk Road in the city of Alameda around 9 p.m. Wednesday after a neighbor called 911. The suspect’s shot father-in-law went to the neighbor for help, Joshi said.

The victim made statements to police before his death, Joshi said.

The other family members were found in the house, where police believe the shootings occurred.

Shane Killian was arrested on suspicion of murder and attempted murder, said Sarah Henry, department spokeswoman.

Henry said Killian did not resist arrest.

Police did not disclose a motive. They said they had seized several firearms in the house.

There is no indication that the public is in danger, the police said. The investigation is ongoing.

This was at least the 21st mass murder in the United States this year, according to a database maintained by the Associated Press and USA Today in collaboration with Northeastern University.

Almost half of the perpetrators – since the database began in 2006 – have killed their own family members.