A town still trying to cope with a deadly bank holdup had another setback Friday when it got word that a state trooper used his service revolver to kill himself, apparently guilt-ridden that he failed to catch one of the alleged robbers a week before.

Nebraska State Patrol trooper Mark Zach, 35, shot himself with his revolver around 1 p.m. CDT just outside of Norfolk.

Zach had stopped one of the robbery suspects, 21-year-old Erick Fernando Vela, on Sept. 19 for a traffic violation and apparently ticketed him for carrying a concealed weapon but transposed two digits when entering the gun’s serial number into a police computer, said Gov. Mike Johanns.

Although the gun was confiscated by authorities, Zach apparently felt responsible for not getting the suspect behind bars on a more serious stolen weapons charge

"Trooper Zach could not accept that," said Col. Tom Nesbitt, Nebraska State Patrol superintendent. "He took his responsibility very, very seriously."

Zach was a 12-year veteran of the State Patrol based in Norfolk. He and his wife had six children, ranging in ages from 4 to 15. He was elected this year as an area chairman for the State Troopers Association of Nebraska.

"This tragedy only compounds yesterday's tragedy," Gov. Mike Johanns said Friday during a somber news conference in Lincoln, hours after Zach shot himself.

The suicide came hours after police laid out their case against the four suspects in Thursday's robbery at the U.S. Bank branch in Norfolk in which five people were murdered.

Norfolk Mayor Gordon D. Adams said he believed the emotional stress of being involved in such a disturbing case could lead a law officer to consider suicide.

"That’s dreadful," Adams said. "It is the kind of fallout you get sometimes with these tragic events."

The three alleged gunmen were caught Thursday in a stolen pickup after stopping at a gas station 75 miles away. A fourth suspect was later arrested. All are from the area.

The holdup men walked in with guns blazing, and within 40 seconds all five victims had been shot in the head, Capt. Steve Hecker testified in dramatic detail at a bond hearing for the suspects.

Hecker said one suspect was asked why they opened fire at the bank, and the man would say only, "It went to hell in the bank." All four men were denied bail.

Hecker said the suspects planned to steal the vehicle of one of the victims. Instead, police say, the three gunmen ran away and stole a car at gunpoint from an elderly couple after breaking into their home. The fourth suspect, the alleged scout, apparently had fled.

About 50 people -- mostly friends of the suspects and relatives of the four bank employees and one customer who were killed -- packed the 30-seat courtroom. The customer's college-age daughter wept in the hallway before the hearing and sobbed in the courtroom every time her mother's name was mentioned.

The suspects sat stoically throughout the hearing, one of them yawning several times. Each suspect faces five counts of first-degree murder, which carries a potential death sentence in Nebraska.

Later Friday, gospel songs sung in both Spanish and English punctuated a Hispanic healing service that drew more than 100 citizens, held two blocks from the bank branch office.

No money was recovered on the men or along their suspected escape route, Norfolk Police Chief Bill Mizner said. An audit was being done at the bank to see if any money was missing.

Three handguns were found along a road between Ewing and Clearwater, the route police believe the suspects used to escape. Investigators had not yet determined if the weapons were used in the crime.

The employees killed were Lola Elwood, 43, Jo Mausbach, 42, Lisa Bryant, 29, and Samuel Sun, 50; the customer was Evonne Tuttle, 37. The suspects were identified as Jose Sandoval, 23, Jorge Galindo, 21, Erick Fernando Vela, 21, and Gabriel Rodriguez, 26.

All the suspects have criminal records, mostly involving drugs and weapons charges. Sandoval and Rodriguez spent time in prison for burglary. Galindo and Sandoval previously had assault charges filed against them.

Franklin Kubes, 25, attended high school with Sandoval and Galindo, and he remembered them as quiet. Kubes also knew the victims: He banks at the branch where the slayings took place.

"I still can't believe they are gone," he said of the victims.

The city held a crisis intervention session for police, fire and other emergency personnel Friday.

The Associated Press contributed to this report.