(NewsNation) — A notebook found in a parking lot and an old phone are two clues that one Georgia woman hopes will lead her to her daughter, who has been missing for four years.

For Jessica Vanzant Deitzel’s mother, Kristina Johnson, the sight of a special photo still brings tears even after four years. She and Dietzel’s daughter, Elana, continue searching for the missing woman.

“It’s ambiguous grief, it’s isolating, it’s horrible,” said Johnson. “Because time keeps going, and you’re just stuck in this place.”

The night Jessica Dietzel vanished

Johnson’s world stopped on Feb. 18, 2020, the last time anyone saw or heard from then 21-year-old Dietzel.

Investigators said Dietzel logged into her Facebook Messenger account using a phone belonging to a man named Gary Potter. That was near a motel in Albany, Georgia, in the early hours of the morning,

The last message sent, seen for the first time on NewsNation, asked a friend to call her and said “I know I’m in too deep…”

It’s not clear how Dietzel knew Potter, but witnesses said the two were also spotted together at the Cowboy Bills Bar, and investigators believe Potter offered Dietzel a ride home.

Lee County sheriff deputies have executed multiple search warrants at Potter’s address and seized items including his truck.

They’ve named Potter a person of interest, with deputies finding a hair inside the seized truck, but they haven’t revealed if that hair could be Dietzel’s.

Searching for Jessica

Potter currently faces a bench warrant on separate charges of child molestation, and his current location is unknown.

Johnson believes something happened that night, either at the motel or at a nearby home where drug activity was suspected.

“They gave her something,” Johnson said. “I think they overdosed or did something to her.”

That theory was bolstered by a tip to a sheriff’s deputy. A confidential informant reportedly told him Dietzel’s body was in a deep freezer and pit at an old landfill.

But Johnson said instead of going to the old site the informant named on Maple Avenue, searchers went to the wrong landfill, focusing on a new Maple Hill facility.

“They didn’t get cadaver dogs over there,” Johnson said. “They didn’t look in the freezers. They didn’t. They dropped the ball.”

Law enforcement frustrations

Johnson said she has been frustrated with the Albany Police Department’s response from the start. She said there was an attitude that Dietzel would show up eventually.

“Don’t do people like that,” Johnson said. “If we come to the place, we know that our person is missing.”

Johnson said she gave evidence to investigators, like one of Dietzel’s notebooks, found in a parking lot six months after her disappearance in pristine condition.

“This stuff had not been sitting there,” Johnson said. “It’d just been put out there.”

Another piece of evidence was a phone that belonged to Dietzel’s estranged husband, containing texts from the night she disappeared asking if she was alive.

“I gave that evidence over to an investigator,” Johnson said. “He didn’t even book it into evidence.”

Johnson said she hoped investigators would take the information she turned over and dig into it to try to find her daughter.

“We can’t just linger on for the rest of our lives. We have to find answers,” she said.

Albany police declined NewsNation’s request for an interview.

As for Johnson, she’s now focusing her pleas for justice on a higher power, praying to bring her daughter home.

If you have information that can help police in the search for Jessica Vanzant Dietzel, please contact police in Albany, Georgia.