Hours of audio captured Rena Nguyen’s distress, her boyfriend’s words and the moments prosecutors later used to establish criminal recklessness.
PROVO, Utah — An audio recording that ran for roughly 14 hours on a college student’s phone transformed the investigation of her 2021 death and eventually became the central evidence in a manslaughter prosecution against her boyfriend. Caleb Aidan Rees, 31, is now serving four consecutive Utah prison terms after admitting reckless conduct contributed to the death of 20-year-old Brigham Young University student Rena Nguyen.
The importance of the recording emerged publicly during a preliminary hearing in May 2025, when Orem police officer Jeffery Randall spent hours testifying about evidence recovered from Nguyen’s phone. One recording began at about 3:20 a.m. on Oct. 1, 2021, and continued for approximately 14 hours. It captured a prolonged argument, Nguyen crying and Rees repeatedly speaking to her in a degrading manner. It also preserved sounds and exchanges surrounding the movement of a handgun and the shooting that followed. That evidence later supported prosecutors’ argument that Rees knew of Nguyen’s suicidal crisis and consciously disregarded an obvious danger.
Investigators had been called to the Orem residence after Nguyen was shot in an upstairs bedroom. Rees reported the shooting, and emergency crews took Nguyen to a hospital. Court reporting from the later proceedings said she died two days afterward. What initially appeared to police as a self-inflicted shooting later became a more complicated inquiry into whether another person’s conduct could amount to criminal manslaughter. The question was not whether Rees fired the weapon. Prosecutors instead focused on what he knew about Nguyen’s condition, how he treated her during the crisis and what he did with a loaded firearm immediately before leaving her alone.
The recording gave prosecutors evidence of those circumstances in real time rather than requiring them to reconstruct the night entirely through later recollections. According to charging documents described in court reporting, Nguyen can be heard sobbing while Rees calls her a liar and a snitch, accuses her of infidelity and tells her she has ruined his life. At other points, prosecutors said he mocked and belittled her and became angry over his belief that she had contacted police. Law enforcement reports later established that a friend had sought the welfare check. The recording documented Nguyen’s emotional state while the confrontation was still unfolding.
Her risk of self-harm was also known before the shooting, prosecutors argued. Hours earlier, Nguyen had sent a friend a message describing having a loaded gun to her head and saying she wanted to live but could not continue under her circumstances. The friend contacted police. An officer reached Nguyen by telephone rather than conducting an immediate face-to-face intervention. Defense counsel later emphasized that decision, arguing that if trained officers believed the telephone contact sufficiently addressed the immediate welfare concern, Rees might also have believed she was no longer in imminent danger. Prosecutors said his direct knowledge during the subsequent argument made his situation different.
One of the most closely examined details involved where Rees placed his handgun. His attorneys said the weapon was initially only inches from the bed and that he moved it to a table about 8 to 10 feet away, an act they characterized as making it less accessible to Nguyen. Deputy Utah County Attorney Adam Pomeroy offered the opposite interpretation at the preliminary hearing. He said Rees could have removed the gun from the room entirely but instead moved it into Nguyen’s line of sight. The prosecution argued that he then walked away while knowing she had been suicidal and was in severe distress.
Randall’s testimony also described sounds on the recording around the time the gun was moved. Prosecutors said the evidence established that after Rees left the room, Nguyen went to the table, took the handgun and shot herself. They did not contend Rees physically forced her to use it. Their theory rested on Utah’s manslaughter law and the allegation that his treatment of her, combined with his knowledge of the risk and his handling of the weapon, constituted reckless conduct that was a proximate cause of her death. Defense lawyers argued the causal connection was too attenuated to sustain criminal liability.
Fourth District Judge Sean Petersen rejected the defense request to end the case at the preliminary stage. In May 2025, after several days of testimony, he ordered Rees to stand trial on manslaughter as well as drug and firearm counts. The ruling did not determine guilt. Under the preliminary-hearing standard, it meant prosecutors had presented enough evidence for the charges to continue. That decision moved the legal focus beyond the fact that Nguyen had fired the fatal shot and toward the narrower question of whether Rees’ own reckless behavior legally contributed to the result.
The recording also altered the case outside the courtroom because Nguyen’s parents had spent years questioning the original handling of their daughter’s death. Rose and Keith Nguyen filed a civil lawsuit in 2023 against Orem police and Rees. Their complaint alleged officers had failed to take sufficient action after earlier contacts in which Nguyen reported abusive conduct and threats involving firearms. It also challenged aspects of the original investigation and advanced allegations about the relationship that went beyond the criminal counts. The claims against the police department were later dismissed after the city invoked Utah governmental immunity protections.
Those earlier police contacts dated back months before the shooting. The civil complaint said Nguyen called 911 in December 2020 and reported that her boyfriend had been handling firearms while intoxicated and was out of control. In June 2021, she sought police assistance while retrieving belongings from the shared residence and reported physical abuse, drug use and a previous threat involving a gun. An officer conducted a domestic violence risk assessment that placed her in a high-risk category, according to the complaint. The lawsuit accused police of failing to act as aggressively as her family believed Utah law and department policy required.
Rees’ defense disputed the family’s description of a sustained history of physical abuse. At sentencing, his attorney rejected the assertion that Rees had repeatedly battered Nguyen before the final day. The defense also maintained that his movement of the firearm had been intended to protect her and stressed that Rees called 911 after the shooting and attempted to provide help. Those arguments remained important at sentencing even after the criminal dispute over guilt ended, because Rees had entered a guilty plea rather than proceeding to a jury trial on the manslaughter allegation.
He pleaded guilty in April 2026 under an agreement that resolved the case with four third-degree felony convictions: reckless manslaughter, two counts of possession of a firearm by a restricted person and a drug offense involving intent to distribute. Reporting on the plea said some counts were reduced and several other gun and drug charges were dismissed. The agreement allowed prosecutors to recommend consecutive sentences. At the July 17 sentencing, Petersen imposed four terms of zero to five years and credited Rees for nearly two years already spent in jail, leaving him exposed to a combined maximum of 20 years.
For Petersen, the evidentiary significance of the phone recording remained clear at the end of the case. He called what it captured “nothing short of horrific” and described Rees’ repeated degrading statements as deeply troubling. Rees told the court he was ashamed and embarrassed by how he had spoken to Nguyen and said he never wanted her to harm herself. Nguyen’s parents, by contrast, said the audio showed their daughter’s fear and the sustained pressure she faced. The court did not need to resolve every allegation made during years of civil and criminal litigation to impose sentence on the crimes Rees admitted.
The recording’s path from a phone seized after a 2021 shooting to evidence heard in a Provo courtroom shows why the prosecution took years to develop. Investigators had physical evidence and a reported self-inflicted shooting from the beginning, but the later case depended on context: what Nguyen had communicated, what Rees knew, what he said and what he did before leaving the room. By July 2026, those facts had moved from disputed allegations in court filings to the basis of a guilty plea for reckless manslaughter and a prison sentence. The criminal proceeding is now resolved, with Rees serving the consecutive terms ordered by Petersen.
Author note: Last updated August 23, 2026.