A search warrant affidavit also reveals that a sister of gunman Peter Selis rushed to the Judicial Drive apartment complex April 30, fearing that he might be involved.
Eve Selis told officers that her brother lived there and was "extremely distraught and depressed" over a recent breakup with his girlfriend, the document says.
The affidavit by San Diego police homicide Det. David Spitzer set out the facts of the case to support the need for a warrant to search Peter Selis' apartment. A Vista judge authorized the warrant about 1 a.m. May 1.
Among the items seized from a bedroom were a full gun magazine, found in the pocket of a chair, and a gun-cleaning kit in the closet. A gun lock was on a desk.
A box for the lock, a bag containing a holster and gloves, and a cardboard box containing syringes lay on the bed.
A computer tablet was on the floor, and a black bag of miscellaneous pills was in the bathroom. The affidavit did not describe the syringes or their possible purpose.
Selis, a 49-year-old auto mechanic, was deeply in debt after two bankruptcies and had been threatened with jail for an unpaid debt. Late Sunday afternoon, he went to the pool at the La Jolla Crossroads Apartments with a duffel bag and sat in a lounge chair.
The area was crowded with many people attending a birthday party.
Selis drank from a beer bottle, then pulled a pistol from the bag, the affidavit says. He started shooting shortly after 6 p.m., and after firing two rounds, he called his ex-girlfriend and told her what he was doing and that police were coming.
One of his victims, Monique Clark, 35, a mother of three, died. The search warrant document said she was shot once in the chest.
Victims were sprawled everywhere, bleeding. Others in the crowd scattered, screaming, and called 911 at 6:06 p.m. A police helicopter arrived seven minutes later.
The helicopter crew told the first officers to head to the pool immediately. They did, and when the shooter saw them "a gun battle began," the affidavit says.
Sgt. Michael McEwen and Officers Jonathan Ferraro and Luke Hammond fired at Selis, and he fired back. He was wounded several times and died there. No officers were wounded.
As news reports of the shooting were broadcast, Eve Selis rushed to the complex and described her brother for police, the court record says. Her description matched the shooter's. She also gave police his apartment number.