OCEANSIDE -- Reginald "Reggie" Grigsby Jr., a football coach at the Army Navy Academy in Carlsbad and the son of an Oceanside police captain, was in jail Wednesday after being arrested on charges of attempted murder for allegedly attacking his mother at his parents' Fallbrook home over the weekend, authorities said.

The elder Grigsby, who reportedly shot and wounded his son to stop the attack, remained on paid administrative leave Wednesday, said Oceanside Police Department spokesman Sgt. Kelan Poorman. It was not clear when he would return to work.

Poorman said the department is investigating the shooting to determine whether Grigsby's actions violated any internal policy or procedure, and the Sheriff's Department is investigating the shooting to see if the off-duty police captain committed any crime.

Sheriff's homicide Lt. Dennis Brugos said the younger Grigsby was arrested early Saturday morning at Palomar Medical Center in Escondido, where he was taken for treatment after being shot. Brugos would not say anything about the 25-year-old's injuries.

Grigsby was guarded in the hospital until Monday, when he was well enough to be transferred to the Vista jail, Brugos said. On Wednesday, he was being held without bail on suspicion of attempted murder. The District Attorney's office had not yet filed charges against Grigsby Wednesday.

He is scheduled to appear in court in Vista Thursday.

Brugos released a few new details of the attack that allegedly prompted a 27-year police veteran to shoot his son.

Grigsby Jr. was arguing with his mother around midnight Friday when he became violent, punching her and choking her, Brugos said.

He said the senior Grigsby tried to get his son away from his wife, but couldn't. That's when he grabbed a handgun, which was not a police-issued gun, and shot his son, Brugos said.

"It was very quick; it wasn't something that dragged on for a long time," Brugos said of the violent sequence of events. "It was very quick and unanticipated by the mother and father."

Desirah Grigsby was either choked or beaten so badly she lost consciousness, Brugos said. She was treated at Fallbrook Hospital for injuries that included a broken nose and has since been released, he said.

Refusing to elaborate, Brugos said investigators were told the younger Grigsby has a history of mental troubles. The former SDSU football player and El Camino High School graduate coaches football and supervises dormitories at Carlsbad's Army and Navy Academy, a private military boarding school of about 300.

Stanford Stockdale, the school's vice president, called Grigsby a "well-liked role model for the kids," and said he remains in good standing with the school.

"Our thoughts are with him and his family as they cope with their personal circumstances," school officials said in a statement issued Wednesday.

Before being hired last fall, Grigsby passed a criminal and employment background check, Stockdale said. School officials are unaware of any history of mental troubles, he said.

The senior Grigsby's actions remain under investigation, and the District Attorney's office will ultimately review the Sheriff Department's case, Brugos said.

Prosecutors review every shooting by an on- or off-duty police officer to determine whether a crime has been committed, said Paul Levikow, a District Attorney's spokesman. He said the office will consider the Sheriff's Department's and the Oceanside Police Department's investigations.

Contact staff writer Sarah Gordon at 760-740-3517.