An 18-year-old suspect has been arrested in a shooting at a library in Northern California that left two people dead. Police say the suspect first walked through the building unarmed, then returned with a shotgun. He fatally shot one person at the entrance and another inside. The shootings occurred Monday evening at the Chico branch of the Butte County Library. Officers arrived within two minutes of the 911 call and apprehended the suspect shortly after. The victims were identified as Jacob Hull and Robert Johnson. The FBI is assisting in the investigation.