TUPELO, Miss. (AP) -- The FBI says investigators used cellphone records to link a suspect to a string of bank robberies in three states, including one in Mississippi that led to the fatal shooting of a police officer.
Daniel McMullen, special agent in charge of the FBI's office in Jackson, Miss., told reporters Sunday that records showed the suspect's cellphone was in Atlanta, Phoenix and Tupelo, Miss., at the time of each incident.
Authorities didn't immediately release the name of the suspect. He was shot and killed by Phoenix police in a bank robbery attempt Saturday.
McMullen said investigators believe the same suspect shot and killed Officer Gale Stauffer and wounded another officer after robbing a Tupelo bank Monday. The suspect also is accused of trying to rob an Atlanta bank earlier that day.
The FBI says that a suspect killed by Phoenix police in a bank robbery attempt is believed to be the same man accused in the shooting death of one Mississippi police officer and the wounding of another.
The statement early Sunday by the Jackson, Miss., FBI bureau came hours after Phoenix police shot and killed the man minutes after Saturday's bank robbery attempt.
The FBI said in an email statement: "We believe that this suspect is the same individual who is responsible for the attempted bank robbery in Atlanta, the robbery of the BancorpSouth in Tupelo, (Miss.) the shooting of Officer Joseph Maher, and the murder of Officer Gale Stauffer."
Phoenix police had no immediate comment when contacted early Sunday.
The slain suspect's name has not been released.
The officers were shot Monday. Stauffer died and was buried Friday. Maher reportedly was able to walk with some aid on Friday.
As authorities continue a nationwide manhunt for a suspected cop killer, law enforcement officials have revealed that the suspected killer and bank robber had attempted a previous bank robbery just before the deadly attack.
Just hours before the suspect robbed a bank and shot two police officers in Tupelo, Miss., authorities say he attempted another robbery in Atlanta, nearly 300 miles away. According to officials, after trying to unsuccessfully rob a Bank of America with a gun, the suspect then walked outside and mugged a person at the ATM.
FBI Special Agent Steve Emmett told reporters the security camera images of the suspect in Atlanta were similar to those in Tupelo.
"Same individual, same day, it's a violent robbery," said Emmett.
On Dec. 23 Officer Gale Stauffer and a second officer were shot when they confronted the alleged robbers at a railroad crossing as they made their escape. Stauffer died of his injuries and the other officer remains in the hospital in serious condition.
The FBI and local police have launched a nationwide dragnet to find unknown suspects, and according to ABC News affiliate station WAPT a reward of $200,000 has been offered to anyone with information leading to the arrest of the suspects. Police are not even sure how many suspects they're looking for, and are hoping that someone saw something in the bloody aftermath of that bank robbery -- or took a cellphone photo -- something that just might help investigators.
Earlier this week residents in Tupelo, Miss., held a candlelight vigil for Officer Gale Stauffer.
Flags were lowered to half-staff in memory of officer Stauffer, an army veteran of the Iraq War, and father of two young children.
"I'm at peace knowing Gale died doing what he loved," said his wife Beth Stauffer.
A funeral service for Stauffer took place on Friday. Stauffer's mother, Debbie Brangenberg, acknowledged those who came to remember her son.
"The overwhelming love and support that this community has given us has helped us make it through," she said.
Stauffer was a combat veteran of the Louisiana Army National Guard, and he had served with the Tupelo Police Department for eight years, according to the Officer Down Memorial Page.
As the officers approached suspects in a vehicle, which was stuck in traffic at a railroad crossing, at least one of the suspects opened fire at close range, according to an account posted online at the Officer Down Memorial Page.
After reviewing bank surveillance video from the robbery of a BancorpSouth bank in Tupelo, authorities are looking for a thin, possibly African-American man with a light complexion, standing between 5-feet-9 and 6-feet tall, according to the Mississippi Department of Public Safety.
The suspect seen in the surveillance video was wearing khaki or cargo-style pants, white Converse tennis shoes, a long-sleeved jacket and a blue ski mask, the state public safety department said. A charcoal-colored, medium-size sedan might have been used as a getaway car.
Anyone with information is asked to call the FBI's tip line at 800-CALL-FBI (800-225-5324).