LEWISTON – Searchers looking for a pregnant woman from Lewiston missing for three weeks found a body Monday in a shallow grave in the city behind a mall.

State police spokesman Stephen McCausland said investigators believe, pending an autopsy, that the body is that of 38-year-old Donna Paradis, who has been missing since Oct. 23.

The grave was found along an ATV trail that runs along railroad tracks.

“The case has changed today from a missing person case to a homicide investigation,” McCausland said.

State and city police investigators spent Sunday trying to narrow the search for a pregnant woman missing since Oct. 23.

On Sunday, Lewiston police and state police troopers, along with about 60 civilian search and rescue volunteers, fanned out across the city to step up the search for the missing woman.

“We had no areas in particular and no information to suggest Donna Paradis was in any harm or danger,” said Lewiston police Sgt. David St. Pierre, head of the department’s Criminal Investigation Division. “We just wanted to eliminate many specifically remote places in the Lewiston-Auburn area where someone could have gone or we could have found something.”

According to the Sun Journal newspaper, police said Paradis last was seen Oct. 23 when she left a job at an East Avenue telemarketing company. Police have questioned co-workers at Affiliated Computer Services as well as those at the Sun Journal, where Paradis, who has daughters 12 and 17 years old, worked nights.

St. Pierre said Sunday searchers had found some items of interest.

“We’ve collected those items and we’re going to review them to see if there is any possibility that they could be related to our missing person,” he said. “Anywhere we’ve searched we’ve found things, like trash that have been dumped. We don’t know if any of it is involved, and we’ve picked it up so we can more closely examine it.”