Left: Jax Gratton (Facebook). Right: Brandon Mumma (Summit County Sheriff's Office).
A Colorado man is accused of wedging his girlfriend's body into a narrow, 4-foot-wide space between buildings and removing all of her belongings from his home after she died under suspicious circumstances.
Brandon Mumma, 41, faces one count of tampering with a deceased human body and one count of tampering with evidence in connection with Jax Gratton's 2025 death in Lakewood, according to the First Judicial District Attorney's Office.
Prosecutors believe Mumma, who appeared in court last week and entered a plea of not guilty, was the last person with Gratton before her death. The two of them were in a "consensual intimate relationship" at the time.
"According to the indictment, Gratton's last active session on her phone was in the early morning hours of April 16, 2025, and used an IP address associated with 9655 West Colfax Avenue in Lakewood," the DA's office said in a March 2026 press release announcing Mumma's indictment.
"Mumma entered the unit at approximately 5:55 a.m.," the release alleged, noting how he was caught on surveillance video. "He remained inside until 6:57 a.m., when he moved his vehicle to the north side of the building. Mumma then entered the building and returned with trash bags, which he threw into a dumpster. Mumma then left the area."
Gratton wasn't seen again by anyone after that night, with her roommate reporting her missing and her family searching the Denver metro area for her.
On June 6, 2025, Gratton's body was discovered between the buildings of 9655 and 9699 West Colfax Avenue in Lakewood. The building at 9699 W. Colfax Avenue was vacant at the time.
"The area where the body was located is a narrow, 4-foot-wide space that is inaccessible to the public," the DA's office said. "It is locked from both ends, requires a key for entry, and features a solid gate on the south side that completely obscures the area from view."
Gratton was found wearing the same set of clothes she had on as she left her apartment on April 15, 2025, which is the last time her roommate reported seeing her. She was found "lying on her side, and a grate from an air conditioning unit was on top of Gratton's lower body," per the DA's office.
"There was a significant dent on top of the air conditioning unit located directly below the north half of the second-story window of 9655 W. Colfax Avenue, Unit G," the DA's press release said, which is the same unit Mumma was seen entering with Gratton.
According to prosecutors, a male friend arrived at 12:14 a.m. and exited the unit with Mumma at 1:43 a.m., leaving Gratton "alone and asleep under the influence of drugs" before her presumed death.
"By the time the unit was searched on May 29, 2025, the furniture from April had been removed from the office," the DA's release said. "None of Gratton's personal belongings, including her cell phone, were ever recovered."
Prosecutors believe that Mumma removed Gratton's body after she died, as well as her personal belongings and other evidence of her death, to avoid detection by the police.
Gratton's autopsy report noted that she had no defensive wounds and there was no clear evidence of pressure on the neck leading to her death, but strangulation could not be ruled out, according to local ABC affiliate KMGH.
The report says aspiration could have also caused or contributed to her death. Methamphetamine, THC, citalopram, and trazodone were detected in Gratton's system, but a drug overdose could also not be proven or ruled out, per the report.
Mumma allegedly told police that Gratton was under the influence of gamma-hydroxybutyrate, or GHB, and took too much that night. He claimed she passed out, started snoring, then began making gurgling noises and vomited. Mumma alleged that he rolled Gratton on her side before leaving with the man mentioned earlier.
When he returned the following morning, Mumma allegedly told police that Gratton was no longer there so he put her belongings in his vehicle. Investigators later ruled Gratton's death a "suspicious death."
Mumma is due back in court on July 30. He is scheduled to go on trial in November.