Hilbun Is Injured in Fall From Jail Walkway : Accident: Authorities say the former Dana Point postal employee who is accused of murdering his mother and a co-worker was exhibiting bizarre behavior at the time of the incident.

Mark Richard Hilbun, the former Dana Point postal worker accused of murdering his mother and a former co-worker, suffered a possible broken vertebrae and a slight concussion Monday in a fall from a second-story walkway in Orange County Jail, authorities said.

Hilbun, 39, who is being held in protective custody without bail, was injured about 7:15 a.m., shortly after being allowed out of his cell for his required time in one of the jail’s day rooms, where some inmates eat their meals and can “relax and watch television,” said Lt. Dick Olson of the Orange County Sheriff’s Department.

“He started to exhibit bizarre behavior and verbally threatened another inmate still in his cell. Hilbun also started beating on the glass door of the inmate’s cell with his hands,” Olson said.

As guards who witnessed the incident summoned a supervisor and medical staff, Hilbun “lay down on his stomach on the second-floor walkway and pushed his upper body out over the day room” on the floor roughly eight feet below, Olson said. After clinging momentarily to the railing, he said, Hilbun “let go, falling to the day-room floor, (where) he landed on his head, neck and upper shoulder.”

Hilbun was alone on the walkway at the time of his fall but was being observed by jail guards in a nearby control tower, said Olson, who added that Hilbun is housed with other inmates in protective custody in a group of second-story, one-man cells.

“Once he slid himself out there, down he went . . . to the next floor, about eight feet,” Olson said.

Olson said Hilbun refused medical treatment immediately after the fall but was later taken under armed guard to a local hospital for treatment.

Hilbun’s attorney, Deputy Public Defender David Biggs, said that jail officials refused to give him any specifics on the fall.

“We’ve called, and the jail (spokesman) said, ‘We’re not giving out any information,’ ” Biggs said.

Olson said that there was no indication that Hilbun was attempting suicide but that the Sheriff’s Department would review the incident and make a determination “of what his intentions were.”

Hilbun is awaiting a preliminary court hearing next month on a variety of felony charges stemming from a bloody, two-day rampage that began in the pre-dawn hours of May 6.

After allegedly stabbing his mother to death in her Corona del Mar apartment, police said, Hilbun drove to a Dana Point post office, where he allegedly shot one fellow postal carrier to death and wounded another before fleeing the scene.

As police carried out a massive, countywide manhunt, Hilbun, whose last known residence was in Dana Point, allegedly shot and wounded at least four more people in three separate attacks in Dana Point, Newport Beach and Fountain Valley.

He was arrested without incident about 12:30 a.m. May 8 while watching television in a crowded Huntington Beach sports bar.

In addition to the two murder charges, Hilbun faces seven charges of attempted murder, three counts of robbery and one count of attempted kidnaping. The Orange County district attorney’s office is considering seeking the death penalty against Hilbun because of the multiple killings and the fact that one of the murders was committed during an attempted kidnaping.

Hilbun had worked at the Dana Point post office nearly four years before he was fired in December, in part for allegedly stalking a female co-worker, Kim Springer of Laguna Beach.

Police contend that Hilbun went to the post office on the day of the killings to kidnap Springer.

Before the shootings, Hilbun had twice been hospitalized for manic-depression and had undergone psychiatric treatment.

He was supposed to be taking lithium, but close friends said he had stopped taking his medication. His attorneys are considering an insanity plea in his defense.

A preliminary hearing has been scheduled for July 6 at South Orange County Municipal Court. The hearing could be postponed if it is determined that Hilbun’s injuries are severe, his attorney said.

Staff writer Lily Dizon contributed to this story.