In People v. Velez (1983) 144 Cal.App.3d 558, the defendant, an officer with the Huron Police Department, was convicted of involuntary manslaughter. On the day in question, the defendant returned to the station after his shift ended and removed his firearm from its holster. He removed the magazine from the weapon and the round that was in the weapon's chamber. He placed the round in the magazine and then inserted the magazine into the firearm. He placed the weapon on or near the dispatcher's desk in the front room of the station and went to change his clothing in another location. A teenage janitor who worked at the station picked up the defendant's weapon. Another teenage janitor also handled the defendant's weapon. Both of the janitors denied they had operated the weapon in any manner before putting it down on a desk. (Velez, supra, 144 Cal.App.3d at p. 562.) Alice Cordero, a 16-year-old office aide at city hall, took some of the defendant's money, which the defendant observed. The defendant jokingly told her she was stealing his money and he would call a cop when she went to the front door of the police station as if to leave. The defendant picked up his firearm and pointed it at her. The weapon discharged, fatally wounding Cordero. (Velez, supra, 144 Cal.App.3d at p. 562.) At trial, the defendant testified he fired the fatal shot but denied placing a round in the chamber of the firearm. He had absolutely no idea how a round entered the chamber. Sergeant Kenneth Abell of the Fresno County Sheriff's Office testified that once the round was removed from the firearm's chamber, it could be fired only by manipulating the slide to place another round in the chamber. He also testified police academy trainees are told to treat all firearms as if they are loaded unless they know otherwise from a personal inspection, and trainees are instructed to refrain from all horseplay with firearms. (Velez, supra, 144 Cal.App.3d at p. 562.) During closing arguments, defense counsel urged it was entirely reasonable for the defendant to believe the gun could not be fired. Defense counsel also emphasized one of the janitors handled the weapon, implying it was a janitor who chambered the round. (Velez, supra, 144 Cal.App.3d at p. 563.) Defense counsel requested, inter alia, a mistake of fact jury instruction, which the trial court refused. (Id. at p. 565.) On appeal, the Velez court held it was not error to refuse defense counsel's request to instruct the jury regarding mistake of fact. (Velez, supra, 144 Cal.App.3d at p. 565.) The Velez court noted the defendant could not be found liable for involuntary manslaughter unless criminal negligence was shown. (Ibid.) As such, neither specific nor general intent was required to be proven because criminal intent was "shown by the defendant's knowing and willful act." (Ibid.) Under the facts of the case, the Velez court held it was only necessary for the defendant "to fail to perceive the risk of pointing a potentially hazardous weapon" at the victim to be guilty of involuntary manslaughter (i.e., criminal negligence). (Id. at pp. 565-566.) Thus, the trial court properly refused a mistake of fact instruction involving the negation of criminal intent. (Id. at p. 566.)