ALGER, Wash. (AP) — Authorities on Wednesday were trying to determine what set off a shooting and stabbing rampage that left six people dead and four wounded, attacks they blame on a drug offender who was released from jail less than a month ago.

The mother of Isaac Zamora said he is "desperately mentally ill" and had been living in the woods. Dennise Zamora said one of those killed Tuesday was a sheriff's deputy who had tried to help their family for years.

Isaac Zamora, 28, was being held Wednesday on suspicion of first-degree murder and attempted first-degree murder.

The shootings began close to Dennise Zamora's house near the small town of Alger. They continued amid a high-speed police pursuit on I-5 and ended in Mount Vernon, about 20 miles south of Alger, when Isaac Zamora turned himself in at a sheriff's office.