(NewsNation) — An Alabama inmate and prison guard involved in a jailhouse romance shared nearly 950 phone calls before escaping and sparking a multi-state search. Police believe inmate Casey White and guard Vicky White, who are not related, may have plotted their escape during one of those conversations sometime between August 2021 and February of this year.

On April 29, video shows Vicky White helping accused murderer Casey White escape the Lauderdale County Detention Center in Florence, Alabama, about 75 miles west of Huntsville.

The intensive 11-day manhunt ended after U.S. marshals tracked Casey White and Vicky White to Evansville, Indiana. The duo led authorities on a chase that resulted in a rollover crash. Vicky White died of a self-inflicted gunshot wound, and Casey White was taken into custody.

Lauderdale County Sheriff Rick Singleton told NewsNation their first priority during the search was finding the missing duo. Now, authorities are digging into the background of how the escape happened in the first place.

“We discovered that they had made 949 phone calls with each other near that period of time from August 21 until he was brought back to Lauderdale County in February,” Singleton said.

Right now, Singleton says, there are investigators assigned to reviewing the hundreds of phone calls, searching for any discussion of escape plans.

“It’s pretty obvious on the surface, but we need all the evidence we can get,” Singleton said. “Part of their defense is that he was in her custody, and he had no part in it. So, we’re looking for any evidence we can find to show that he was an active participant and a willing participant.”

Sheriff Singleton said before the manhunt, his employees never had any inkling there was a relationship between Casey White and Vicky White.

“Still, even to this day when it comes up around the office, my employees are still in disbelief that Vicky would have pulled this off,” Sheriff Singleton said.

He explained that Vicky White had given no indication that she was capable of participating in an escape.

Singleton says the biggest thing he learned from the manhunt is: “You have to be careful about who you put your trust and confidence in.”

Casey White has been charged with murder in the death of Vicky White. His latest move in the case was requesting a transfer to a different jail.