At about 2:50 p.m. officers responded to the Antioch Community Center, located at 4703 Lone Tree Way, on a report that a person was assaulting people inside the library, according to police.
Witnesses said the suspect, identified as Antioch resident Kenneth Johnson, fled the scene in a blue van prior to officers arriving at the scene, police said.
Officers determined that Johnson physically attacked two library employees without any provocation, prior warning and for unknown reasons.
A patron inside the library attempted to intervene and was also assaulted by Johnson, police said.
According to officers, Johnson took money from the wallet of one of his victims before leaving the community center.
Police said Johnson was located nearby a short time later. He was driving north on Lone Tree Way in his van. Police conducted a traffic stop and a verbal confrontation ensued. Johnson was then taken into police custody without incident.
He was arrested on suspicion of felony assault and robbery. He was then transported to the Contra Costa County Detention Facility in Martinez, according to police.
Both librarians were transported to area hospital with injuries not considered life-threatening. The third victim was treated and released at the scene, police said.
The motive for the assaults remain under investigation. Police said none of the victims knew Johnson prior to the attack.
Anyone with information about the incident is asked to call Antioch police at (925) 778-2441 or may text a tip to 274637 using the keyword ANTIOCH.