Two officials told the Associated Press that Ms White, 56, had taken the 38-year-old capital murder suspect out of Lauderdale County jail for 40 minutes and then returned him to his cell.
It is not clear exactly when the dry run took place but, after it was an apparent success, the couple then embarked on the real thing on 29 April.
The shocking revelation comes as new details continue to emerge about the couple’s escape plan and how the nationwide manhunt played out.
The search came to a dramatic end on Monday as a police chase in Indiana resulted in the inmate back in police custody and the corrections officer dead from what officials say was a self-inflicted gunshot wound to the head.
US Marshal Marty Keely gave a detailed account of the investigation and nationwide manhunt to the AP, revealing that the US Marshals Service was called in to assist about three hours after Lauderdale County sheriff’s officials noticed the pair had disappeared.
Ms White picked the inmate up from Lauderdale County jail at around 9.30am claiming that she was taking him for a mental health evaluation at Lauderdale County Courthouse.
She told her coworkers that once she had escorted him to court she was going to seek medical attention for herself as she felt unwell.
The pair never arrived at the courthouse.
At first, law enforcement officials believed White might have kidnapped Ms White, but they quickly learned that she had made up the mental health evaluation and so a manhunt began.
The Gulf Coast Regional Fugitive Task Force sprung into action and received an early tip from a fellow jail worker who said that Ms White had called and asked them to pick her up at an Academy Sports + Outdoors store in Florence, Alabama.
Ms White claimed she had locked her keys in her car and needed a ride to work, Mr Keely said.
The employee said they thought it was strange but wanted to help out a friend.
Authorities descended on the parking lot of the store and found Ms White’s patrol car there — the same vehicle which had been used in the prison escape.
Surveillance footage from the scene then captured a getaway vehicle – an orange Ford Edge she had purchased just days before the escape with a fistful of cash.
Following interviews with family members, coworkers and other inmates, and after examining financial and other records, officials discovered that Ms White had a “special relationship” with White.
Weeks before the escape she sold her house for $95,000, far below the market value, sold her car and filed for retirement, Mr Keely said.
She had also bought an AR-15 rifle and a shotgun to add to her 9mm service weapon and a .45-caliber pistol investigators believe she had.
The corrections officer had also bought men’s clothes at a local Kohl’s store and had also visited a store that sold sex toys.
By this time, the couple had already left the state and were almost 200 miles (322 kilometres) away in a different vehicle.
Mr Keely said the next breakthrough in tips came when a tow truck driver from Williamson County, Tennessee, called and said he had towed the Ford Edgethree or four days earlier and it was still in his tow yard.
After scouring rural Tennessee looking for clues, investigators found a home with a few cars and trucks for sale on the lawn.
The homeowner instantly recognized a photo of the inmate and helped authorities piece together what had happened.
He told investigators he sold White a Ford F-150 pickup truck for cash. The truck didn’t have licence plates, but White didn’t care, the man told authorities.
“He says, ‘Yeah, I sold him a truck,’” Mr Keely said of the homeowner.
“And so, we learned that he sold him a truck the same day that they escaped from the Lauderdale County Correctional Facility. And it was just a few hours after they had escaped.”
During the sale, a woman in an orange Ford pulled up and the two drove off trailing one another, the man told authorities. He also gave authorities the pickup truck’s vehicle identification number or VIN.
The Whites had abandoned the Ford Edge and made their way to Evansville, Indiana, in the pickup truck.
There, White also abandoned the latest getaway vehicle in the bay of a car wash.
They picked up a new getaway car – a Cadillac – and paid a homeless man to rent a room in Motel 41 for them for 14 days.
The manager of the car wash first noticed the abandoned pickup truck on 3 May and called police the next morning.
But when an officer came out and ran the licence plates, they found the car wasn’t stolen and so left it. The officer did note the vehicle’s VIN in a report.
The car wash owner had the vehicle towed himself.
On Sunday, US Marshals spotted the matching VIN as they searched databases for the couple’s getaway car and headed to Evansville.
Surveillance footage captured White and the pickup at the car wash. It also showed the Cadillac, leading task force investigators to drive around checking out motels and restaurant parking lots, Mr Keely said.
An officer spotted the Cadillac in the parking lot of the motel, which is based just across from Vanderburgh County Sheriff’s Office.
A taskforce began surveillance on the motel and witnessed the suspects leaving – Ms White wearing a wig as a disguise – getting into the Cadillac and driving away.
The US Marshals secretly tailed them, but the officers were seen and a police chase began, according to Mr Keely.
The pursuit ended when officers rammed the couple’s car off the road into a ditch and, at some point, Ms White shot herself in the head, authorities said.
Officers pulled White from the car first who blurted out: “Please help my wife, she just shot herself in the head,” Mr Keely said.
It is not clear why he referred to the corrections officer as his wife with officials confirming they were not married.
White was cuffed and led away while Ms White’s limp body was pulled from the car, gun in hand.
She was given medical aid on the scene and rushed to hospital where she was pronounced dead.
Officials said the couple had about $29,000 in cash, four handguns and an AR-15 rifle in the Cadillac.
White told investigators that he was prepared to have a shootout with police when he was captured, officials said.
White is now back in Alabama in a maximum security prison as he awaits his June trial for the 2015 murder of a 58-year-old woman.
He is already serving a 75-year sentence for a 2015 crime spree including the attempted murder of his ex-girlfriend.
He was charged on Tuesday with prison escape in the first degree.
Ms White’s body has now been returned to Alabama following the completion of her autopsy, where the coroner ruled her death a suicide.
Associated Press contributed to this report