The missing, pregnant wife of a Marine might have been shot while hunting in California with a married man with whom she was having an affair, court document show.

Erin Corwin, 20, who disappeared more than three weeks ago, had planned to meet with her neighbor, Christopher Brandon Lee, to spend a “special day together” on a hunting trip, according to court filings cited by the Desert Sun on Monday.

“It is highly likely that Erin could have been harmed by an unknown firearm,” investigators wrote in the documents. “Sometime after Erin left with Lee, her phone was deactivated (turned off). Detectives believe if Erin was injured and left at an undisclosed location, she would not (be) able to call for help.”

A number of people have been interviewed in the disappearance of Corwin but no suspect has been named.

Lee, 24, a former Marine, told detectives he was not with Corwin on the day she disappeared. He said he went hunting in Joshua Tree National Park.

Corwin disappeared on June 28 after she left her Twentynine Palms home. Investigators say she previously said she was headed to the park. Her husband, Marine Cpl. Jonathan Corwin, reported his wife missing the next day.

The investigation has come to focus on Lee, who may have been the father of Corwin’s child, according to an affidavit filed by San Bernardino County sheriff’s Detective Corey Emom.

Read more from the Associated Press at the Washington Times