Suspect Arrested in New Mexico Mountain Biker’s Murder on Trail

A New Mexico mountain biker who was on a ride was found dead with several gunshot wounds. The suspect, who was arrested, has a disturbing history.
A Fort Bayard trail near Silver City, New Mexico. Photo: John Fisch

A 29-year-old New Mexico man has been arrested as part of an investigation by New Mexico State Police in the death of mountain biker Stephen Timmons, according to KRQE News.

Police responded to a call to check in on a missing person on June 26, 2023 who had not returned home after a ride. Officers found Timmons’ vehicle at the Dragon Fly trailhead near Silver City, New Mexico. Search and rescue teams were deployed in the area and found the victim dead with gunshot wounds.

On July 7, the New Mexico Department of Public Safety (DPS) matched shell casings and projectiles at the murder scene with a firearm Joseph William Costello had in possession at the time of a previous arrest, according to KRQE.

Timmons was a minister for a Western New Mexico University program. An obituary says Timmons was a devoted Christian who “loved and respected everyone regardless of who they were or where they came from.” He is survived by his wife, parents, sister, two sons, a daughter, and two grandchildren.

Costello has a reported history of confronting, “chasing, and threatening people,” at public locations such as campgrounds and public trails. There were also reports in the past year of a person matching Costello’s description threatening trail users and possibly firing gunshots at them. He had an active warrant from another county for trespassing when he was arrested after being stopped by a U.S. Forest Service officer for a traffic violation on a motorized bike on June 30.

Costello published hundreds of videos on YouTube where he displayed unusual behavior and signs of paranoia and delusion, according to the Albuquerque Journal. Costello told followers how he believed he was being stalked and spied on by different individuals.

The Journal also reports that Costello used a police officer’s taser against the officer and a partner while he was under arrest in 2018, but the case was dismissed for “unknown reasons.” Three years later, Costello was also suspected of pointing a crossbow at a family floating in the Rio Grande river, but the case was dismissed too because Costello was deemed “not competent to stand trial.”

A KVIA article from 2022 details Costello’s disturbing behavior in Doña Ana County, New Mexico and that he had been chasing and threatening community members for months while he camped near a river.

Sources told KVIA that Costello would run out of the bushes screaming at locals, including kids and elderly persons and had shot at them with a crossbow. Results with law enforcement were uneventful. Costello was arrested multiple times but always released from jail.

“We can only do so much,” Sheriff Kim Stewart told KVIA, calling it a “revolving door situation.”

Costello is currently being held at the Grant County Detention Center while State Police investigate the case. He has been charged with murder.