Washtenaw County Sheriff's Office spokesman Derrick Jackson said the wallet was found about 12:30 p.m. Tuesday, May 26, on Bridge Road near Ford Lake in Ypsilanti Township, about a mile from Tonya Jackson's former apartment.
He said the Washtenaw County Sheriff's Office Underwater Search and Rescue Team would be entering the water Tuesday afternoon near where the wallet was recovered.
Derrick Jackson said the dive team would be searching for Tonya Jackson's 1997 silver Saab SUV, which hadn't been seen since her disappearance. They would be searching for any physical evidence that would link someone to the disappearance. They also would be searching for Tonya Jackson's body.
Earlier dives into Ford Lake did not turn up any information in her disappearance.
Before Tuesday, the only other clue detectives had to go on was a note found written on tissue at an Englewood, Ohio, Steak 'n Shake.
The note, believed by detectives to have been written by Tonya Jackson, had her name on it and referenced a man named John Samuel who was driving a red Chevy Cavalier.
"We needed something new, but I have mixed emotions about (her wallet being found)," Evans said. "I'm glad they found something, but it doesn't necessarily make me feel better about her (being found alive)."
Crime scene investigators spent the early part of Tuesday afternoon searching the area for clues, while detectives talked to two women at the scene, as well as LV Jackson, Tonya Jackson's husband, after he was called there by detectives.
A K-9 unit searched a nearby wooded area for more than 30 minutes, but Derrick Jackson did not have any information about that search.
For several hours after the wallet was discovered, at least five WSCO trucks and two detective vehicles were on the scene before the dive team arrived.
"Since the beginning, I've prepared myself for the worst, but prayed and hoped for the best. I know Tonya would never just walk away from her kids, no matter what was going on at home," Evans said.
"My sister is a fighter and a strong person. There is still hope that she's alive."
Derrick Jackson said the dive team is paying attention to the weather, and impending storms may interfere with the team's efforts, but added the team will stay in the water as long as it can.