Erin Corwin is twenty years old and pregnant. She is also missing. The young wife of Lance Cpl. Jonathan Corwin was last seen on June 28th at the couple’s home in the southern California Marine base known as Twentynine Palms. She reportedly told her Marine husband that she was setting out to visit the nearby Joshua Tree National Park and has never been seen since.

“We are looking for a crime scene,” Leland Boldt, captain of the San Bernardino County Sheriff’s Specialized Investigation Division, said in a press release on Tuesday.

“Although suspicious circumstances have existed from the inception of this investigation there is still not enough evidence to rule out that Erin Corwin could be voluntarily missing,” the press release also stated.

One of the most bizarre facets of this mystery is the purported reason Erin Corwin was headed out to explore the Joshua Tree National Park. It was–according to reports–as a means of celebrating that pregnancy by another man. Apparently Lance Cpl. Jonathan Corwin–Erin Corwin’s husband–isn’t her baby’s father. A man named Christopher Brandon Lee is instead. Officials believe Corwin was having an affair with Lee.

Documents written by case investigators state that Corwin may have been shot while hunting with Lee, a married ex-Marine, in what was intended to be their “special day together” on a hunting trip.

Christopher Lee was arrested and subsequently released on Tuesday on suspicion of possession of a destructive device. Sheriff’s spokeswoman Jodi Miller said he was arrested as a result of a search warrant in an ongoing investigation, but she wouldn’t provide any further details, nor say any more about the destructive device Lee is suspected of owning.

UPDATE: Man who knew Erin Corwin, missing & pregnant marine's wife, arrested http://t.co/X6eBCwAPL0 via @nbcsandiego pic.twitter.com/2mdvaGOE3D

— Dateline NBC (@DatelineNBC) July 22, 2014

“It is highly likely that Erin could have been harmed by an unknown firearm,” detectives wrote in these court 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.”

It was via an affidavit filed by Detective Corey Emom that the media learned of the alleged affair. A friend of Erin Corwin’s turned in text messages she received from Erin indicating that she and Lee were involved in a romantic relationship and that the two had a day trip planned for June 28th.

It’s uncertain if Jonathan Corwin learned of his wife’s pregnancy by another man before or after she went missing. He reported Erin Corwin missing on June 29th. Police found her car–a 2013 Toyota Corolla–in Twentynine Palms on June 30, but declined to say much about the vehicle.

Local media reports say Corwin told investigators that his wife–who is a volunteer horse rescue worker–wanted to go check out the park in advance of a planned family visit. The Corwins are originally from Oak Ridge, Tennessee, and Erin Corwin’s mother had planned to visit her for her birthday in the coming weeks. Erin Corwin and her mom had already purchased tickets to visit SeaWorld, according to authorities, and Erin had no known medical or psychological issues.

What do you think happened to Erin Corwin? Did her husband harm her in a fit of rage after learning she was pregnant by another man? Or did Christopher Brandon Lee harm her instead before word leaked out to his wife that he had gotten another woman pregnant? Have investigators taken a good look at Christopher Lee’s wife? Whether or not any of these scenarios prove true, it still doesn’t sound–as the press release states above–that Erin Corwin has gone ‘voluntarily missing.’ It’s a lot more likely, unfortunately, that something far more sinister is at play instead.

Image via Twitter