After a six-month investigation, police have arrested a Nevada man for the murder of his girlfriend Laura Johnson.

According to the affidavit, security footage shows Laura, 49, arriving at the Billings, Montana home she shared with boyfriend Gregg Green around 7:00 p.m. on September 13, 2018. While the affidavit states security footage shows Green working in the yard when Laura arrived home, Green reportedly told authorities he last saw Laura that morning before he left for work, and that she was gone when he arrived home in the evening.

Laura Johnson Billings Police Department

“[Green] told [investigators] that [Laura] took her two suitcases and other belongings with her,” the affidavit states. “[Green] claimed that this type of behavior from [Laura] was not unusual,” so he did not report her missing to authorities. Laura’s son reported her missing on September 28 after not hearing from his mother for a few weeks. Police previously told Dateline they soon conducted a search warrant on the home Laura and Green shared, as well as a search warrant on Green’s employer-provided truck.

“[Green] was present and consented to the search. According to [authorities, Green] was very cooperative and the officer noted that the residence was very clean,” the affidavit states. “[Green] also allowed [authorities] to look through his smartphone.”

The affidavit continues to detail text messages Green sent to Laura in the days following her disappearance. One of the messages, in part, reads: “I hope your [sic] happy with your new guy.”

On October 5, according to the affidavit, authorities reviewed security footage from one of Green’s neighbors. Officers noted the footage was “of good quality” and the camera pointed in the direction of Green’s home, capturing the events around the time of Laura’s disappearance.

“According to their review of the surveillance they could observe [Green], on September 14, 2018 at 5:48 p.m. carrying a very heavy object, ‘cradle style’ out of his garage,” the affidavit states, adding that the object was “covered in a red colored blanket” and was “consistent with the size and shape of a body.”

Authorities say Green then placed the body in the rear cab of his truck before starting a small fire toward the rear of the pickup, which was parked in the driveway. Investigators “could not determine what [Green] was burning at the rear of the truck.” Authorities say Green then put a shovel into the bed of the truck and drove away around 7:00 p.m. Through further investigative efforts, the affidavit states that authorities were able to determine that Green then drove to a rural area south of Laurel, Montana before returning home at 10:23 p.m. that night.

A truck of interest in Laura's case. Billings Police Department

“At no time on September 14, 2018 did the video recording show Laura Johnson exiting or walking from the residence,” the affidavit continues.

In subsequent interviews with investigators, Green “downplayed any relationship that he had with [Laura].” A second search of his residence lead investigators to discover “very new” carpet in the bedroom. A neighbor also told investigators he heard Laura and Green “really, really getting into it” during a fight the night Laura was last seen.

Days later, “three small visible reddish brown stains” found on a door of Green’s truck were swabbed and sent to the Montana State Crime Lab for testing. After comparing the swabs to Laura’s parents’ DNA, a forensic DNA analyst reported “very strong evidence” that the blood stains found on the truck belong to Laura.

Laura’s boyfriend Gregg Green, 53, was arrested on April 17 on a felony charge of Deliberate Homicide, a Billings Police Department press release stated. Despite repeated searches, police say they have been unable to find Laura’s remains or a possible burial site.

“The Billings Police Department is requesting the assistance of land owners and the public in [Billings, Laurel, Shepherd, Worden, and Huntley, Montana] in locating Mrs. Johnson’s remains,” a press release states. “Please be on the lookout for potential burial sites, ground disturbances, and any evidence of two red rectangular suitcases.”

If you have any information on the circumstances surrounding Laura Johnson’s death, please call the Billings Police Department Investigations Division at 406-657-8473.