All five people injured worked at the casino restaurant, and authorities said none suffered life-threatening injuries.
LINCOLN, Calif. — A restaurant employee accused of stabbing five coworkers inside a kitchen at Thunder Valley Casino Resort appeared in court Friday on attempted murder charges, two days after deputies arrested him at the Northern California property.
The Placer County Sheriff’s Office identified the suspect as Joseph Naugle. Authorities said deputies responded around 7 p.m. Aug. 19 to a reported stabbing at the Dos Coyotes restaurant inside the casino. Officers arrived within minutes and took Naugle into custody. Investigators said the five injured people and Naugle all worked at the restaurant and that no casino guests were involved.
The stabbing occurred in the restaurant’s kitchen rather than on the casino floor, according to casino officials. One injured worker was taken to an area hospital, while four others were treated at the scene by Thunder Valley Casino emergency medical personnel and Cal Fire. Authorities said all five suffered injuries that were not considered life-threatening.
Investigators said Naugle appeared to know all five people who were injured. Authorities have not publicly identified the workers or disclosed what may have led to the attack. No motive had been announced as the investigation continued, and officials have not released a detailed account of what happened immediately before the violence.
News cameras at the casino recorded Naugle being placed into a sheriff’s vehicle following his arrest. He appeared to still be wearing work clothing, including a kitchen apron. Authorities booked him into Placer County custody in connection with the attack. An arrest and criminal charges are allegations, and they do not establish guilt.
The Sheriff’s Office said shortly after the stabbing that investigators were not looking for additional suspects and that there was no continuing threat to the public. Thunder Valley Casino remained open after the incident, while the restaurant area was closed as investigators worked at the scene. Casino officials said the incident was limited to restaurant employees and did not involve patrons.
Published reports initially differed on Naugle’s age, with some outlets listing him as 22 and another reporting that he was 23. Because of that discrepancy, his age could not be independently established from the material reviewed. Reports otherwise agreed that the Sheriff’s Office identified Naugle as the employee taken into custody following the stabbing.
Naugle appeared in court Friday for arraignment on attempted murder charges, according to prosecutors cited by CBS Sacramento. A public defender was appointed to represent him, and his next court appearance was scheduled for Wednesday. Authorities have not announced a motive, and the Sheriff’s Office continues to investigate the circumstances surrounding the attack.
Author note: Last updated August 22, 2026.