The car she was driving when she was last seen was found in the lake Thursday afternoon.
Her estranged husband reported her missing on Tuesday.
Investigators said they don’t suspect foul play based on the evidence they currently have.
Ohio State Highway Patrol Lt. Brian Aller said it looks like the car ended up in the water because of a traffic crash. Law enforcement also believes Bass-Jefferies was the only person in the car when it went into Buck Creek.
“But we will look at all the different types of evidence that we have right now to see if it’s anything else,” Aller said.
The last known person to see Bass-Jefferies was Natalie Driscoll. She drove Driscoll to Springfield the evening of Jan. 18, and Driscoll said she appeared stressed.
“She seemed stressed out to me,” Driscoll said. “That was our first time hanging out just me and her. I date her cousin, so anytime we are together, it’s always at a family gathering or something.”
Driscoll said Bass-Jefferies dropped her off around 7 p.m. She was driving a car that belongs to her estranged husband.
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Aller said the body was found “several hundred yards” from where crews were looking.
Aller said the family was grief-stricken.
Law enforcement searched the lake because Bass-Jefferies’ cellphone last pinged in that location. Aller said they spotted the car under the water and ice using a helicopter.
Dayton Police Lt. Jason Hall said investigators also are actively working the case.
“Investigators worked diligently utilizing all avenues available to find Bass-Jefferies, and as a result were led to Buck Creek State Park,” Hall said.
The Ohio State Highway Patrol, Clark County Sheriff’s Office, Piqua Fire Department, Wright-Patterson Air Force Base and the Ohio Department of Natural Resources all worked with Dayton police to find the car and Bass-Jefferies.
Driscoll said she called and texted Bass-Jefferies after she dropped her off, but didn’t think anything of it when she didn’t answer.
“We had a couple of drinks, and she had plans to go to a male friend’s house in Dayton. I thought maybe she just got caught up with that,” Driscoll said.
She knew something was wrong when Bass-Jefferies’ sister called her, asking if she had heard from her.
Since then, Driscoll described the search for her friend as a “living nightmare.”
“(Buck Creek) is 20 minutes from my house. I live right by the highway, if she was going to turn around and go right back to Dayton, I don’t see how she could have gotten out here,” Driscoll said. “I don’t even know why she would have been down here by the loading dock.”
Hall asked those who may have information on Bass-Jefferies to call police at 937-333-COPS or contact Miami Valley Crime Stoppers at 937-222-STOP.