Gabriel Rodriguez, 26, had been driving the getaway car and apparently abandoned the three others, Mayor Gordon D. Adams said on CBS' "The Early Show."
Police found Rodriguez after locating the Cadillac he was believed to be driving, Police Chief Bill Mizner said. The car was parked in a southeast Norfolk neighborhood. The other three escaped by stealing a vehicle at gunpoint from a house near the bank, authorities said.
They were apprehended at a gas station a few hours after the holdup.
All four men were being charged with five counts of first-degree murder, which carries a potential death sentence in Nebraska, authorities said. Mizner said authorities don't believe anyone else was involved.
Three handguns were recovered on the roadside between Ewing and Clearwater, along the route that police believe the suspects fled after the robbery. Police, volunteer firefighters and volunteers on all-terrain vehicles were combing the roadsides for evidence.
"We have recovered no money. Part of the investigation will include doing an audit to figure out if any money was taken," Mizner said.
The suspects were surrounded by police when they stopped for gas and food in O'Neill, 76 miles northwest of the robbery in Norfolk. The town's police chief, Ben Matchett, said he could not disclose what led him and two other officers to the men and the stolen pickup they were driving.
Holt County Attorney Tom Herzog said the three men matched descriptions of the suspects.
The men were identified by police as Jose Sandoval, 23, of Norfolk; Jorge Galindo, 21, and Erick Fernando Vela, 21, both of Madison. A bond hearing was scheduled for Friday.
Four employees and a customer were killed at the U.S. Bank branch in Norfolk, a one-story, stucco building in the middle of a strip mall parking lot. Another customer was shot in the shoulder.
Mizner had tears in his eyes as he read the victims' names at a news conference. The employees — Lola Elwood, 43, of Norfolk; Jo Mausbach, 42, of Humphrey; Lisa Bryant, 29, of Norfolk; and Samuel Sun, 50, of Norfolk — and customer Evonne Tuttle, 37, of Stanton, were found dead at the scene.
"In your heart, you honestly believe that stuff happens someplace else. It can't happen here," Mizner said.
He said it was unclear what went on inside in the bank, though the wounded customer and two unharmed employees may be able to help. Investigators were screening the bank's security tapes.
The robbery occurred shortly before 9 a.m.; the suspects were arrested about three hours later.
After leaving the bank through a shot-out glass door, the gunmen broke into a nearby house where they confronted the home's residents at gunpoint and stole their car, Mizner said. No one in the home was injured.
The suspects drove about 10 miles, ditched the vehicle and stole a pickup truck, Mizner said. Authorities tracked down the first vehicle, a Subaru Outback, by using its satellite navigation system.
The killings stunned Norfolk, a community of 25,000 people about 90 miles northwest of Omaha that is best known as the hometown of comedian Johnny Carson.
As news of the crime spread, Gov. Mike Johanns declared a state of emergency and authorized the use of a Black Hawk military helicopter for the manhunt. Roadblocks were set up throughout the area, schools in Norfolk were locked down, and many banks either closed or allowed only drive-through window transactions with customers.
Dale Tomka, a florist, said he saw the gunmen shortly before the shootings wearing stocking caps, possibly ski masks. One had black stripes on his cheeks, he said.
Mizner said authorities had not determined why the bank door was shot out, but it may have simply been shattered by the gunfire inside.
A stray bullet shattered a drive-through window at a Burger King next door to the bank. No one inside was hurt.
"I screamed and said, `My God, I think somebody shot the building!" said Donna Schwager, who was working a cash register near the window. "The good Lord was looking out for me today."