The man, who is from Petersburg, hid the weapon when he walked into Octapharma Plasma center and asked to use the restroom, Petersburg police Capt. Emanuel Chambliss told CNN. The suspect then later attacked people inside the center, injuring four, Chambliss said.
People inside the center ran out through the back door and called police, according to Chambliss. The suspect waited for police to arrive.
“He was sitting in a chair waiting for us,” Chambliss said.
The suspect was arrested at the scene. Police have not released his identity.
Three women and one man were transported to a local hospital, police said.
Two victims were in surgery Thursday night and listed as being in serious condition. Two victims were treated and released, according to Chambliss.
Petersburg is south of Richmond.