SAN DIEGO COUNTY, CA – A remote canyon killing that began with erratic behavior and escalated into a violent series of attacks has ended with a 216-year prison sentence for a 42-year-old man convicted of murdering 59-year-old Samuel Holthaus.
Kenneth McNally Jr. was sentenced late last week after a jury found him guilty earlier this year on all counts related to the September 2023 killing in Harbison Canyon, about 25 miles east of San Diego. The convictions included first-degree murder, shooting at an occupied vehicle, assault likely to cause great bodily injury, and two counts of assault with a semiautomatic firearm.
“This was an extraordinarily violent and disturbing case involving a defendant who terrorized multiple victims before committing a cold-blooded murder and attempting to conceal the crime,” said San Diego County District Attorney Summer Stephan. “Because of the courageous witnesses who came forward, and the relentless work of law enforcement and prosecution team…this dangerous defendant is being held fully accountable for his heinous crimes.”
Grisly discovery in Harbison Canyon
The violence unfolded on Sept. 3, 2023, on a six-acre property where McNally had been intermittently staying in a trailer owned by acquaintances. Authorities said he was “aggressively demanding rides off the property” and appeared to be concealing a weapon in his jacket.
Witnesses later told investigators that McNally admitted to killing Holthaus. “McNally confessed that he had killed Holthaus and dragged him down a hill with a noose around his neck,” one witness told law enforcement. A second witness reported a similar confession and said she saw McNally driving the victim’s truck erratically before parking it near a grave site.
Deputies responded to Harbison Canyon Road around 3:30 p.m. after receiving reports of a suspicious death. Hours later, they uncovered the body.
“Holthaus’ body was discovered buried in a shallow grave after a witness noticed the top of the victim’s head protruding from the ground,” according to the district attorney’s office. “Investigators found an extension cord wrapped around the victim’s neck and observed a gunshot wound to the side of his face.”
Evidence of dragging, shooting detailed
Investigators found Holthaus’ truck near the grave with blood on the driver-side door, along with drag marks leading to another area where coagulated blood and burned debris were located.
Months later, a third witness provided further detail about the killing. “[H]e saw McNally shoot Holthaus. According to the witness, McNally then tied one end of an electrical cord around Holthaus’s neck and attached the other end to Holthaus’s truck,” prosecutors said. “McNally drove the truck 329 feet to the location where the body was ultimately found, dragging Holthaus’s body by his neck.”
McNally was arrested on Sept. 6, 2023, at a motel in El Cajon. Deputies recovered a bag of bloody clothing; while most of the DNA belonged to McNally, one stain matched Holthaus.
Prosecutors said the murder followed a pattern of escalating violence on the property in the weeks before the killing. Incidents included threatening someone with a handgun, firing multiple rounds into a van occupied by another man, and strangling a roommate before the attack was interrupted.