MODESTO (AP) — Two teenage girls stabbed in Northern California on Saturday are in stable condition at a hospital, and that a third younger victim is improving, authorities said.

Modesto Police Sgt. Ivan Valencia says the stabbings of the girls, two 13 and one 11, was reported about 1 a.m. Saturday during a sleepover.

Authorities said one of the teenagers appeared to have stabbed the other two before turning the weapon on herself.

The circumstances surrounding the attacks were being investigated.

Valencia said it isn’t clear if the teenage suspect could face charges but that police and prosecutors would meet with probation and social services to discuss the best course of action.