An Alabama woman found dead inside a police van parked outside Huntsville Police Department headquarters earlier this month may have become trapped inside.

The woman, identified as 29-year-old Christina Nance, was captured on security camera video entering the unoccupied vehicle nearly two weeks earlier on the afternoon of Sept. 25.

However, no one immediately noticed the intruder.

Twelve days later, on Oct. 7, an officer walking by saw a pair a shoes on the ground next to the van and then discovered Nance’s body inside, according to NBC News, which cited a statement by Huntsville Police Deputy Chief Dewayne McCarver.

McCarver said the van should not have been unlocked and that the doors could not be opened from the inside because it was once used to transport inmates.

“Because of its original design, it does not have handles on the inside because it was made for transporting prisoners and inmates,” McCarver said, according to NBC. “You cannot exit from the interior of the van.”

The van was last used in March and had been parked in the back of the department’s public safety complex. It was most recently used to transport evidence to be destroyed after cases were closed.

“What stresses us and pains us, … cars go by. People walk near the van,” McCarver said, according to NBC. “We just wish she would have hollered out to someone or something because there was, unfortunately, potential opportunities for this not to be a tragedy.”

Investigators have relied on the videotaped footage to retrace the woman’s steps before she entered the van on Sept. 25.

Nance, who is Black, was filmed wandering the police department parking lot that night, lying down in some bushes and sitting on the hood of a police car, NBC reported. Video footage revealed that she opened the van’s windows three days later, on Sept. 28, McCarver said, according to NBC.

The woman’s family reported her missing Oct. 2.

An autopsy showed no signs of foul play but an official cause of death will be determined by the state medical examiner, according to Madison County Coroner Dr. Tyler Berryhill.