Haley Rippetoe’s former boyfriend was already facing kidnapping and assault allegations when investigators say he followed and killed her.
GREELEY, Colo. — A protection order was in force and a previous criminal case was pending when prosecutors say Justin De Nileon Jr. followed his former girlfriend from work, intentionally crashed into her vehicle and killed her beside a rural Weld County road.
The death of 28-year-old Haley Rippetoe has focused attention not only on the evidence collected at the June 21 crash scene near Erie, but also on the legal history that preceded it. De Nileon, 29, had been arrested in May in a separate case accusing him of kidnapping and assaulting Rippetoe. Her relatives told police that he had been emotionally and physically abusive during the relationship, and the arrest affidavit in the murder case says a protection order was active when she died. De Nileon is now charged with first-degree murder after deliberation and is being held without bond.
Rippetoe’s father, Ryan Rippetoe, told KUSA that his daughter had questioned whether the order could stop someone who was willing to violate it. After her death, he said the system had failed her. His statements reflected the family’s anger and grief, but the publicly available records do not provide a complete account of how the earlier case was handled, what conditions were imposed on De Nileon or whether authorities received any reported violations before June 21. The protection order’s existence is documented in reporting on the affidavit; its full terms have not been publicly detailed.
Family members gave investigators a history that they believed explained why Rippetoe remained at risk. They recalled alleged threats and physical confrontations, including an incident in which De Nileon was said to have shoved her and another in which he allegedly tried to run her vehicle off a road. The affidavit also quoted an alleged threat to injure her during a domestic dispute. Those claims have not been proven at trial, and De Nileon is entitled to challenge them. They are significant to the investigation because police say the fatal encounter itself also involved a vehicle being used to force Rippetoe from the roadway.
The June 21 sequence allegedly began after Rippetoe finished work. Investigators say De Nileon followed her as she drove through the area and then struck her Nissan Rogue with his white SUV near Weld County roads 7 and 6. The impact caused the Rogue to roll off the road, according to prosecutors. Authorities allege that the collision was intentional rather than accidental and that Rippetoe survived it. What followed, prosecutors say, was a separate attack outside or partly inside the damaged vehicle.
Erie police arrived at about 1 a.m. and found Rippetoe dead near the driver’s side of the Nissan. Officers did not accept the scene at face value. The location and amount of blood did not fit an accidental crash or an ejection, the Weld County District Attorney’s Office said. The arrest affidavit described blood inside the driver’s area and along much of the exterior driver’s side. Investigators also found damage that they believed had occurred after the collision, including a broken driver’s window and a seat belt that appeared to have been cut.
The belt was still secured in its buckle, but its upper portion had a clean cut consistent with a sharp object, according to the affidavit. Other marks suggested repeated attempts to sever it. Investigators believed the opening in the driver’s window could have been made by someone trying to get into the Rogue. Those details supported the allegation that another person approached Rippetoe after the rollover, forced access to the vehicle and removed her while she was restrained by the belt. Prosecutors accuse De Nileon of pulling her from the SUV before killing her.
An autopsy separated the cause of death from the crash itself. The medical examiner found multiple sharp-force injuries that were not consistent with a traffic collision, according to the affidavit. Investigators concluded that the wounds were deliberately inflicted with a sharp instrument. Authorities have not publicly identified a weapon, and the released information does not state whether one was recovered. The affidavit’s description establishes the prosecution’s theory, but the medical and physical evidence will remain subject to examination through the court process.
Rippetoe’s relatives were alerted to the incident before they received a call from an officer. Her brother and sister received automated iPhone crash notifications and drove toward the location. They arrived to find police at the scene. Ryan Rippetoe received a similar notification. When an officer told him his daughter was dead, he immediately suggested that De Nileon might be involved, the affidavit said. Police noted that he was extremely emotional and did not initially explain the basis for his suspicion, but relatives later described the history of alleged abuse and threats.
Investigators then examined De Nileon’s conduct after the collision. Surveillance video allegedly showed a white SUV leaving the area. Phone records indicated that he called his parents and sounded panicked, according to the affidavit. His parents asked Broomfield police to check on him. Officers later found him at their home, allegedly hiding beneath a tent. He had cuts and abrasions on his hands and suspected blood on his clothing. Investigators said the amount of blood did not appear consistent with his minor injuries.
Police treated those circumstances as parts of a connected chain: the alleged pursuit from Rippetoe’s workplace, the vehicle impact, the forced entry suggested by the window, the cut seat belt, the autopsy findings, the departure of a matching SUV and the condition in which officers located De Nileon. The district attorney’s office filed one count of first-degree murder after deliberation. In Colorado, the wording of the charge signals that prosecutors are alleging an intentional killing committed after deliberation, but the filing itself is not proof of guilt.
The case also presents questions that the released records do not answer. Authorities have not announced a motive. They have not said whether Rippetoe contacted police or relatives during the alleged pursuit, whether the crash notification recorded additional data or whether investigators recovered communications sent between Rippetoe and De Nileon that night. Officials have not released the complete file from the May case or explained how the protection order was monitored. Those gaps should not be filled with assumptions while the prosecution remains pending.
De Nileon appeared before a judge for an initial advisement and remains in the Weld County Jail without bond. His next scheduled appearance is Sept. 2 at 10 a.m. in Division 15. He is presumed innocent unless proven guilty. The murder case will determine criminal responsibility for Rippetoe’s death; the surrounding history has already left her family asking how a woman covered by a court order could still be reached by the person it was intended to restrain.
Author note: Last updated August 3, 2026.