Thirty-one-year-old correctional officer Jeremy Kingstrom is recovering from stab wounds to the face and neck, after the Sunday evening attack in the prison yard.

Meanwhile, officials say 19-year-old Joel Campos and 25-year-old Felipe Ruiz are being held in solitary confinement after being charged with attempted murder of an officer.

Both men already are serving life sentences—Campos for kidnapping and carjacking, and Ruiz for attempted murder and gang activity.

Pelican Bay is located 13 miles south of the Oregon border and houses 3,400 minimum and maximum security inmates.