Transcript for FBI Expands Search for Possible Multiple Gunmen in Robbery

the massive nationwide manhunt. What police could believe, in fact, multiple gunmen in tupelo, mississippi, bank robbery. An officer was shot and killed during a chase. Police believe the suspect or suspects may be heavily armed, as well. Abc's ron claiborne here with the very latest on the search to find all of them. Ron, good morning to you. Good morning, josh. That manhunt covering parts of mississippi, arkansas and alabama. The suspects are being called the christmas cop killers. But authorities aren't even sure how many people they're looking for. This morning, police in mississippi and now the fbi, expanding their manhunt for this suspected cold-blooded cop killer. This image captured by a surveillance camera as he was about to rob the bank in tupelo. Police say a short while later the suspect, possibly with one or more accomplices, gunned down police officer gale stauffer and wounded joseph maura. We have a number of agencies that are working in unison, in a unified manner to solve this heinous crime. Reporter: Authorities are looking for this man, they call a person of interest. This photo taken at a convenience store by a security camera just before the bank robbery. And another video shows what police say was the suspect's car as it left the parking lot after the robbery. I want to, again, publicly appeal to all citizens. If you have any information, please get that to law enforcement. Reporter: In tupelo this christmas weekend, normally a fee occasion, there was a candlelight vigil. And flags lowered to half-staff, in memory of officer stauffer, an army veteran of the iraq war and the father of two young children. I'm at peace with gale because I know he died doing what he loved. Overwhelming outpouring of love and support that this community has given us, has helped us make it through. Reporter: There's now $162,000 reward for information leading to the arrest of the bank robbers-turned-killers. The search for them covering three southern states. And investigators are hoping that someone saw something in the bloody aftermath of that bank robbery. Maybe even took a cell phone photo that bears a clue, anything that might help them find these guys. Later, the funeral for officer stauffer. And good news, the wounded policeman is upgraded from critical to stable. We go to a tragedy at a

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