Two Georgia inmates who shot and killed a pair of correctional officers before escaping a prison transport bus remain on the run Wednesday.

Donnie Rowe and Ricky Dubose overpowered the guards on the bus traveling on Highway 16 southeast of Atlanta Tuesday morning. Rowe and Dubose stole the guards' guns and shot them before hijacking a passing car they used to flee.

Local authorities, the United States Marshals Southeast Task Force, the FBI and the Georgia Bureau of Investigation joined forces to search for the two men.

Read: Inmates Kill 2 Prison Guards In Putnam County, Georgia Before Escaping

“We have no idea where they are,” Putnam County Sheriff Howard Sills said during a press conference Tuesday. “We are searching everywhere in America. They could be anywhere.”

It remains unclear just how the prisoners were able to overpower the guards on the bus. A total of 33 inmates were on board the bus and the correctional officers were separated by a gate.

“I can’t tell you how they got through the gate,” said Sills. “I still have their blood on my shoes.”

The officers killed were identified as Christopher Monica and Curtis Billue, both long-standing members of the department.

After killing the officers, Rowe and Dubose stole a car from a man who had stopped to provide assistance to what he thought was a stranded bus. Police said the two men robbed the driver at gunpoint before fleeing in his car.

The inmates reportedly broke into a home in Morgan County, Georgia, later Tuesday. Rowe and Dubose stole food and clothes and changed out of their prison garments, which they left inside the home.

“According to the City of Madison [Police Department], the inmates broke into a residence there and got clothes, left their prison whites and made their escape from there,” the Oconee County Sheriff’s Office said Tuesday night. “The inmates and their vehicle have not been recovered.”

Another tip led authorities to a Family Dollar store in Madison where witnesses said they saw the pair.

“We do have confirmation that they were in the Family Dollar earlier [Tuesday] afternoon,” said Sills, noting that authorities were doing a “grid search” to the north and south of the area.

Authorities upped the reward for information leading to the capture of the inmates from $60,000 to $70,000 Wednesday, though they said that amount could increase as more organizations become involved.

“We may add more resources if this is a protracted manhunt,” said FBI spokesperson Steve Emmett, according to the Atlanta Journal-Constitution. “These two individuals have proven themselves to be extremely dangerous and with the murder of two correctional officers they are on the radar of all law enforcement in Georgia.”

Dubose and Rowe are thought to be armed with the Glocks they stole from the slain officers.

“My biggest concern is that they’re going to kill someone else,” said Sills.

Rowe, 43, was convicted of armed robbery, possession of a firearm during a crime and aggravated assault in 2001 and was serving a life sentence without parole.

Read: Inmate Hanged In Cell Dead For 10 Hours While Guards Watched Netflix

Dubose, 24, was convicted of financial identity fraud, credit card fraud, burglary by forced entry, theft by taking and entering a vehicle, aggravated assault, armed robbery and theft in 2010 and 2014 and was sentenced to 20 years in prison. At one point, he also took $100 from an acquaintance at gunpoint before shooting him in the hand, according to Elbert Sheriff’s Office Captain Darren Scarborough. Dubose was known to be in an Aryan prison gang called “the Ghostface Gangsters.”

“He’s off the chain,” said Scarborough. “He’s just a loose cannon. He’s well known to us. He’s very dangerous and he has nothing to lose and I think he will go down in a blaze of glory. And that’s sad because some officer will have to answer for shooting him.”