Seattle police detectives are investigating after three people were injured in a Tuesday night assault.

Officers were called to the 11500 block of Stone Way North just after 10 p.m. for a report of a domestic-violence assault involving a knife, according to a post on the Seattle Police Department blotter.

When officers arrived, they found three people with stab wounds: a 9-year-old boy, a 67-year-old woman, and a 27-year-old woman who is believed to be the suspect, police said.

All three people were taken to Harborview Medical Center, police said. The two women were said to be in critical condition, while the boy’s vital signs were stable.

Information from The Associated Press is included in this report.