A man was busted in the murder of his girlfriend’s 15-year-old daughter in West Virginia who had been missing for more than a week, authorities said.

Andy J. McCauley Jr., 41, was arrested Thursday in connection to the death of Riley Crossman, who was last seen May 8, the Morgan County Sheriff’s Department said in a press release.

He’d been a “suspect since day one,” Sheriff K.C. Bohrer said at a press conference, according to local station WHSV.

The development came after local authorities on Thursday discovered a decomposed body they believe to be Crossman’s over an embankment in a rural mountain road area, police said.

Only a pathologist can confirm that the body is indeed Crossman’s, but investigators are confident that it is hers, authorities said.

The body was transported to the state medical examiner’s office for a Friday autopsy.

McCauley had been under surveillance at his job site in Berkeley County, before investigators asked him to come into a West Virginia State Police office, Bohrer said, according to the local station.

McCauley was arrested there, and is expected to be charged with murder, though the degree will be up to the prosecuting attorney, Bohrer said.

Authorities have no reason to suspect that anyone else was involved, according to Bohrer.

Crossman’s mom reported her missing when she learned that the teen hadn’t showed up to the Berkeley Springs High School on May 8.

Exactly a week after her disappearance, more than 300 volunteers gathered to help police search for any sign of Crossman, according to the report.

Authorities said this wasn’t the conclusion they’d hoped for, but they are glad the family has closure, and are requesting prayers for all who knew her.