Gunman Kills Man in Hall of Courthouse : Violence: A suspect is arrested in San Bernardino in the death of his ex-girlfriend’s father. Shots reportedly followed an argument over child custody.

A gunman opened fire in the San Bernardino County courthouse Thursday, killing his ex-girlfriend’s father and sending bystanders in the hallway, some of them children, scurrying for cover, authorities said.

The victim was identified as Melvin Davis Robinson, 45, of San Bernardino. He had come to the courthouse with his daughter, who was scheduled to attend a child custody hearing with her ex-boyfriend, Lynn Waller, 30, of San Bernardino.

Witnesses heard three shots fired and soon afterward police arrested Waller who had been pointed out by witnesses, said Police Department spokeswoman Sherrie Guerrero. Police also recovered a weapon, but did not immediately say what type.

Before the scheduled custody hearing, Robinson’s daughter and Waller were involved in a heated argument, police said. The child was not present.

“The suspect began to threaten the victim’s daughter,” police said. “When the victim attempted to mediate the argument, he was shot.”

Waller was questioned most of the day by detectives who said they planned to book him for investigation of murder, said Greg Timpany, a police spokesman.

“Detectives learned that the victim’s family had sought to obtain restraining orders against the suspect because of past threats,” Timpany said.

About 40 officers searched the courthouse grounds for another man believed to be involved, but it was discovered there was only one gunman, Timpany said. A handgun was recovered but there were no details on the type used in the killing, he said.

“All of a sudden you just heard a big bang and I looked up, I mean, it was fast. You could see the fire and the gun went off two more times and I saw a person fall. Everybody ran,” said witness Connie Simpson.

The shooting occurred at 9:40 a.m. in a third-floor hallway outside Superior Court. Dozens of people in the corridor dropped to the ground or ran for cover.

The courthouse was closed to the public for several hours while officers combed the grounds and searched for the weapon. The 200 to 250 courthouse workers remained on their jobs.

People entering the courthouse, 60 miles east of Los Angeles, are not screened by metal detectors, which are in place in many courthouses in the country.

Use of metal detectors has been under consideration, said Fea Herrick, director of court services. Searches have been conducted only during special cases.

Nine people have been slain in courthouses in the United States this year.