JEFFERSON COUNTY, Colo. — The last person known to have been with Jax Gratton — who was missing for two months before her body was found in Lakewood in June — has been indicted on two counts connected with her death. He was arrested in Summit County on Wednesday.
Brandon David Mumma faces one count of tampering with a deceased human body and one count of tampering with evidence, according to the First Judicial District Attorney's Office. The office said on Wednesday afternoon that it believes he was the last person who was with Gratton before her death, and the two were in a consensual intimate relationship at the time.
Mumma is expected to appear in court on Thursday.
Watch Denver7's latest update on this case from Wednesday's newscast in the video player below.
A grand jury for Jefferson and Gilpin counties returned the two-count indictment, alleging that Mumma had removed Gratton's body from where she had died — as well as her personal belongings and other evidence of her death — to avoid detection by investigators.
The grand jury indictment was presented to the district attorney's office on Monday, and a warrant was signed for Mumma's arrest. He was taken into custody in Summit County on Wednesday and has a $100,000 cash bond on the indictment, the district attorney's office said.
Denver7 has requested a copy of the indictment.
Gratton, 34, was last seen on the evening of April 15, 2025. In the days after her disappearance, her loved ones searched the metro for her.
According to information from the indictment released by the district attorney's office, Gratton and Mumma entered an office space at 9655 W. Colfax Avenue at 10:41 p.m. on April 15, 2025. A second man arrived at 12:14 a.m. and left the unit with Mumma at 1:43 a.m. At that point, Gratton was alone and asleep under the influence of drugs, the district attorney's office said.
Security cameras confirmed that nobody entered or exited the unit Gratton was inside until Mumma returned at 5:55 a.m. He stayed there until 6:57 a.m., when he moved his car to the north side of the building, according to the indictment. It alleges that he went into the building again and returned with trash bags, which he threw into a dumpster before leaving the area.
The second man has been cooperative with law enforcement and is not believed to have been criminally involved in this case.
Gratton's phone last pinged early on April 16, 2025, using an IP address associated with that office space on W. Colfax Avenue.
The unit was searched on May 29, 2025, but by that time, the furniture that had been there in April was removed and none of Gratton's personal belongings, including her cell phone, were recovered, the district attorney's office said.
On June 6, 2025, police in Lakewood announced that they were investigating a suspicious death after a bystander had discovered a body in a narrow space — about 4 feet wide — that is inaccessible to the public between the buildings of 9655 and 9699 W. Colfax Avenue.
"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," the district attorney's office said.
On June 7, 2025, Gratton's mother, Cherilynne Gratton-Camis, announced on Facebook that the body was her daughter. Gratton-Camis said a detective was able to identify the body by the tattoos. At that point, Gratton had been missing for about two months.
Police continued to investigate this case. On June 10, 2025, the Lakewood Police Department ruled Gratton's death suspicious. This announcement spurred a wave of her loved ones to call for an independent oversight task force to look into the handling of her death investigation.
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In August, Denver7 obtained Gratton's autopsy report, which revealed the coroner's findings about her death. The autopsy was completed on June 8. Her severely decomposed body was discovered under a second-story window of the Lakewood building, which was referred to as an apartment by the coroner's report though the district attorney's office called it an office building on Wednesday. The top of an air conditioning unit directly under that window was dented, the report reads, and Gratton's head was found resting on a cinder block supporting the air conditioning unit. The report read that because so much time had passed, officials were not able to establish a cause and manner of death.
At some point, Gratton used gamma-hydroxybutyric acid, fell asleep and then woke up and vomited, Mumma told authorities, according to the coroner's report. The report adds that Mumma reported that he and the second man propped Gratton up and left the apartment and when Mumma returned to the unit, Gratton was no longer there.
Denver7 reported on these findings in August. Watch that below.
Gratton did not have any defensive wounds and there was no clear evidence of pressure on the neck leading to her death, but strangulation cannot be ruled out, the autopsy report reads. Aspiration could have also caused or contributed to her death, the report reads. While methamphetamine, THC, citalopram, and trazodone were detected in Gratton's system, a drug overdose could not be proven or ruled out, the report reads.
"The effects of postmortem decomposition have made it impossible to prove or rule out multiple possible mechanisms of death, including complications of drug use, accidental blunt force injuries, assault by another, or some other scenario," the autopsy report concluded.
As such, the cause and manner of death were listed as undetermined.
Mumma is expected to make his first appearance on Thursday.
