Two off-campus shootings in Augusta are believed to be related to two on-campus shootings at Paine College, the Richmond County Sheriff’s Office said today. All four shootings happened during a two-day span.

On Sunday, a shooting was reported in the 1300 block of Laura Street, according to Sgt. Michael McDaniel. Later that afternoon, shots were fired at a Paine College dorm, injuring a student, McDaniel said.

Then, on Monday, two additional shooting incidents were reported, according to police. The first took place at the same Laura Street residence, McDaniel said.

Then, at 1 p.m., Paine College was locked down due to an active shooter on campus. Nearby Georgia Regents University was also locked down, according to campus leaders.

In that incident, a student, JaJuan Baker, 21, was critically injured after being shot in the head, according to police. One suspect, Xavier Cooper, has been arrested in that incident.

Investigators believe all four shooting incidents are related, McDaniel told The Atlanta Journal-Constitution today. But additional suspects and arrests are possible as the investigation continues, he said. Cooper has not been linked to additional crimes at this time, McDaniel said.

Cooper's father told The AJC his son could not have been involved with crimes Sunday. Cooper has been charged with aggravated assault, possession of a firearm during the commission of a crime and having a weapon in a school building, Richmond County jail records show. He was being held without bond tonight.

A news conference will be held Wednesday at 10 a.m. at Paine College to provide an update on the investigation, McDaniel said.