Cheyenne Man To Plead Guilty For Shooting Teen While Playing With Gun

Tirso Munguia, 19, of Cheyenne, has agreed to plead guilty to shooting a 16-year-old girl in the head in January while handling a 9 mm pistol in exchange for dropping max sentence from 20 to 12 years in prison.

Clair McFarland

May 04, 20233 min read

Tirso Munguia, 19, has agreed to plead guilty in the accidental shooting death of a 16-year-old Cheyenne girl in January.
Tirso Munguia, 19, has agreed to plead guilty in the accidental shooting death of a 16-year-old Cheyenne girl in January. (Cowboy State Daily Staff)

The 19-year-old Cheyenne man accused of killing a teenage girl with an ill-timed gunshot in January has agreed to plead guilty. 

Tirso Munguia and his attorney filed a plea agreement Tuesday in Laramie County District Court in which Munguia agrees to plead guilty to involuntary manslaughter. 

The charge is punishable by up to 20 years in prison, but the Laramie County District Attorney’s office has agreed to cap its sentencing recommendation at 12 years in exchange for Munguia’s guilty plea.  

District Attorney deputy William Edelman also plans to argue for no fewer than eight years in prison, according to the agreement.  

Munguia also agreed to pay any victim restitution.  

If a Laramie County District Court judge refuses to accept Munguia’s plea agreement, he will still not be allowed to withdraw his guilty plea, the document says.  

The Car Ride 

The District Attorney’s office charged Munguia in January with killing Angelina Harrison, 16, who died of a 9 mm gunshot wound to her head.  

Munguia told police he was sitting in the back seat of a car next to Cody Nicholson, 18, when Nicholson took the pistol out of his sweatshirt pocket and put it in the seat between them, according to the evidentiary affidavit in the case.  

Harrison sat in the front passenger seat.  

Munguia began handling the gun.  

“Be careful, there’s one in the head,” said Nicholson, who was looking at his phone.  

The pistol “just went off,” the men told police. A bullet struck Harrison in the head. She bled from her mouth and became unresponsive.  

The car parked in the Frontier Mall parking lot, and police arrived and found Harrison on the ground outside the car, while Munguia tried giving her medical aid.  

Ankle Monitor 

Munguia’s defense attorney, Steven Iberlin, also filed a request for bond reduction Tuesday, asking the court to switch Munguia’s $75,000 cash-only bond to a possible surety bond. If he’s released, the request says, Munguia would pay for his own GPS ankle monitor.  

Iberlin reasoned that Munguia may be unlikely to violate his bond conditions if he’s freed, because he would lose the benefits of his plea agreement if he did so.  

The victim’s family has agreed to the bond modification, Iberlin’s request says.    

Meanwhile, On The Way To Trial 

Nicholson is charged with felony accessory after the fact for allegedly running away on foot before police arrived and hiding the pistol at his grandmother’s house.  

Nicholson is still scheduled to go to trial Aug. 14.  

He faces up to three years in prison.   

Clair McFarland may be reached at

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Clair McFarland

Crime and Courts Reporter