LAKEWOOD, Colorado — A 41-year-old man is now facing criminal charges after his girlfriend’s body turned up hidden in one of the most unlikely places investigators had ever seen — a narrow, locked gap between two buildings that the public could not access.
Brandon Mumma was indicted in March 2026, nearly a year after Jax Gratton vanished without a trace.
He has pleaded not guilty.
The Night Gratton Disappeared
The last time Gratton’s roommate saw her was the evening of April 15, 2025.
Her phone’s last active session was recorded in the early morning hours of April 16 — connected to an IP address tied to 9655 West Colfax Avenue in Lakewood, the unit where Mumma lived.
Surveillance footage allegedly captured Mumma entering the unit at 5:55 a.m.
He left at 6:57 a.m., moved his vehicle to the north side of the building, then re-entered and came back out carrying trash bags. He threw them into a dumpster and left the area.
Gratton was never seen alive again.
Body Found Nearly Two Months Later
Her family searched the Denver metro area. Her roommate filed a missing persons report.
Then, on June 6, 2025 — nearly seven weeks after she vanished — Gratton’s body was found.
She was wedged into a 4-foot-wide space between 9655 and 9699 West Colfax Avenue. The neighboring building was vacant.
“The area where the body was located is a narrow, 4-foot-wide space that is inaccessible to the public,” the First Judicial District Attorney’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 lying on her side, still wearing the same clothes from the night she disappeared. An air conditioning grate was resting on top of her lower body.
A large dent was found on the AC unit directly below a second-story window of Mumma’s unit.
What Mumma Told Police
Mumma gave investigators his own version of events.
He claimed Gratton had taken GHB that night and that she passed out, started snoring, then began gurgling and vomited. He said he rolled her on her side and left with a male friend who had been at the unit.
When he returned the next morning, Mumma told police she was simply gone — so he packed up her belongings and put them in his vehicle.
None of Gratton’s personal belongings, including her cell phone, were ever recovered.
By the time investigators searched the unit on May 29, 2025, the furniture that had been there in April was already gone too.
The Medical Findings
Gratton’s autopsy did not find defensive wounds, and there was no clear evidence of pressure on her neck. But strangulation could not be ruled out.
Aspiration was also flagged as a possible cause or contributing factor to her death. Methamphetamine, THC, citalopram, and trazodone were found in her system — though a drug overdose could not be confirmed or eliminated either.
Investigators ultimately classified her death as a “suspicious death.”
What Comes Next
Mumma appeared in court last week and entered a not guilty plea. He is due back in court on July 30 and is scheduled to go to trial in November.
Prosecutors allege he moved Gratton’s body, removed all evidence of her death, and attempted to avoid detection — charges he is now fighting in court.
What do you think happened that night? Share your thoughts in the comments below.
