A sheriff's office in the US state of Alabama said on Monday that they had expanded the search for an inmate and corrections officer who have been missing since Friday.

The US Marshals also announced that it was offering a $10,000 (€9,500) reward for information on the pair, who left the Lauderdale County Detention Center on the pretext of an appointment that didn't exist.

"We consider both of them dangerous and in all probability both of them are armed,'' US Marshal Marty Keely said at a Monday press conference.

CO handed in her retirement papers

According to law enforcement, Casey Cole White, who had been jailed on a capital murder charge, was escorted by corrections officer Vicky White, allegedly to attend a mental health evaluation at court. The two are not related.

Not only is it against policy for an inmate to be escorted off-site by a single officer, officials later said, it also became apparent later on Friday that Casey White, 38, had no such appointment.

Vicky White, 56, had been a corrections officer for 25 years. Lauderdale County Sheriff Rick Singleton said she had handed in her retirement papers the previous day.

Authorities have said that Vicky White was armed at the time of the incident. Singleton added that his office was probing how much contact they had had before Friday's events, and that an arrest warrant had been issued for the officer who let an inmate leave without a second escort.

The vehicle they had left the jail in was later found abandoned in a shopping center parking lot.

AP material contributed to this report.