( CNN ) -- The body of a missing pregnant wife of a Marine based in California was found over the weekend and her former neighbor was arrested in connection with her death , police in San Bernardino County said . Erin Corwin , 19 and three months pregnant , had been missing since June 28 after she said she was going to Joshua Tree National Park to scout trails . On Saturday , searchers found her body about 140 feet down a mine shaft but were n't able to recover and identify it until the next day , San Bernardino County Sheriff John McMahon said . An autopsy determined Corwin had been killed , the sheriff 's department said , without elaborating how she died . On Sunday night , authorities in Anchorage , Alaska , arrested Christopher Lee , who police say had been having an affair with Corwin . CNN affiliate KTLA , citing District Attorney Michael Ramos , reported that charges against Lee will be decided in the next two days . KTLA also reported that it may take four to five weeks before he can be returned to California . The station said Corwin 's husband , Cpl . Jonathan Corwin , has n't spoken publicly about the case . Suspect from the beginning . Corwin did n't go to Joshua Tree National Park on the day she disappeared , police said in a statement of probable cause written in July . Instead her car was found a few miles from where she lived next door to Lee and his wife , Nicole . Detectives found footprints next to Corwin 's abandoned car that led to tire tracks . Investigators said those tire tracks were the same width and same width apart as the tires on Lee 's Jeep . According to the court document , several people , including a friend of Erin Corwin 's in Tennessee , told investigators that Corwin and Lee were having an affair . He admitted to kissing her but told detectives the two had never had sexual intercourse . Lee also told police that on the day Corwin disappeared he had gone hunting . San Bernardino County deputies arrested Lee on July 4 for a felony not related to Corwin 's disappearance : possession of a destructive device . KTLA said he posted bail two days later . The search . More than 100 mine shafts were searched before the sheriff 's team found Corwin 's body . Authorities used cell phone information to narrow the search area to 300 square miles . The area included remote land belonging to the federal government 's Bureau of Land Management . On Saturday , searchers went to the Brooklyn , Los Angeles and Rose of Peru mines . KTLA described the area as remote and off a dirt road accessible by four-wheel drive vehicles . Searchers located Corwin by using a camera , the sheriff 's department said . Because the body was so far from the surface and the air in the mine was poor , it took another day to get to the body and bring it to the surface .
Former neighbor is arrested in connection with her death , which has been ruled a homicide . Erin Corwin went missing June 28 , same day neighbor says he was out hunting . Neighbor was arrested a week later , but in connection with another alleged crime . Corwin was three months pregnant , authorities say .