Man Shoots Ex-Girlfriend, Bystander at El Toro Base : Crime: The gunman, a former Marine, is also believed to have made a bomb threat to the facility just before the shootings.

An ex-serviceman entered El Toro Marine Corps Air Station with a pistol Friday morning and shot two Marines in the head, one his former girlfriend and the other apparently an innocent bystander, authorities said.

The gunman, armed with a 9-millimeter automatic, critically wounded Staff Sgt. Deborah L. House, 31, who has been stationed at El Toro for three years, and Cpl. Patrick D. Crudup, 20, who has been at the base for two years.

FBI officials said House, who was taken to Western Medical Center-Santa Ana, was not expected to survive. Crudup was reported in stable condition at the hospital.

Shortly after the 10 a.m. shooting, military police arrested Aldaten Leonard Bush, 30, a former Marine. Base officials said he also is believed to be the one who called the airfield 10 minutes before the shootings began and made a bomb threat.

After being held in the base detention facility, Bush was turned over to the FBI, which has jurisdiction over crimes committed on federal installations.

He was taken to the Metropolitan Detention Center in Los Angeles Friday evening and is expected to be arraigned Monday afternoon on charges of attempted murder, crimes on a government reservation and possibly murder before a U.S. Magistrate in Santa Ana, said James M. Donckels, a senior agent with the FBI.

“Bush was the ex-boyfriend of House,” Donckels said. “He had been making several calls to the victim in attempts to see their 8-year-old son. He had been making threatening calls to House from his home in South Carolina and told her that he was going to try and see his son and if anyone got in his way, he would deal with them.”

Bush reportedly had threatened House in the past, including a 1986 incident in which he allegedly pointed a double-barreled shotgun at her when she was stationed at Twentynine Palms, Donckels said.

According to the FBI, Bush reportedly fired shots at House in a parking lot on the base Friday. He then chased her into a building where witnesses reported hearing several more shots being fired. It is believed that Crudup was hit then, Donckels said.

House then ran into a bathroom and was followed by Cpl. Todd Grotberg who joined her in trying to hold the bathroom door shut. Donckels said Bush began firing shots through the door, hitting House in the head.

Grotberg, who was not shot, escaped through the bathroom window as Bush reportedly stuck the gun through the door and continued firing, Donckels said.

Bush, still holding the gun, then surrendered to military police who arrived on the scene immediately after the shootings, Donckels said.

Both victims were taken to Western Medical Center-Santa Ana. A Marine Corps helicopter evacuated one victim, while the other was taken to the hospital by military ambulance.

Capt. Betsy Sweatt, a Marine spokeswoman, said that about 10 minutes before the shooting, a chaplain on the base received a bomb threat that turned out to be a hoax. The chaplain notified military police, who immediately clamped down on security, closing all entrances and exits to the base.

By that time, however, the gunman had entered El Toro. Sweatt said that perhaps the suspect had a military decal on his car that allowed him to get by sentries or he called the base ahead of time to get clearance for a visit.

The burst of gunfire took place in a normally quiet area of the base filled with administrative buildings and an open-air pool for base personnel.

The shooting reportedly caused a flurry of rumors on the base that a sniper was engaged in a mass shooting.

“A huge rumor got started,” said Lt. Beth Carreiro, assigned to El Toro’s public affairs office. “People were calling, asking us about the sniper.”

Times staff writers Greg Hernandez, George Frank and David Reyes contributed to this report.