Investigators say surveillance footage and telephone records supported a witness account describing the hours before Carmen Lizet Puch was killed.

GREAT FALLS, Va. — The case against a 19-year-old man accused of killing his 42-year-old co-worker near a Northern Virginia trail is built on several types of evidence that police say trace his actions from their workplace to the secluded parking area where she was found dead. Alexis Antonio Cedillos-Campos faces a second-degree murder charge in the Aug. 17 death of Carmen Lizet Puch, a Reston resident and mother who worked with him at a restaurant in Herndon.

Fairfax County police initially released relatively few details when officers found Puch near her Honda Civic in the parking lot of Difficult Run Park shortly before 7 a.m. Investigators later described a much broader case. Police and court documents cited in local news reports point to restaurant surveillance footage, telephone records, a co-worker’s account, gloves and a gasoline-smelling bottle recovered at the scene, and statements authorities say Cedillos-Campos made after his arrest. Those elements are allegations and investigative evidence; they have not been tested at trial, and the second-degree murder charge does not itself establish guilt.

The most detailed account of a possible motive emerged later from a witness cited in a criminal complaint. According to reports describing the document, the witness told investigators that Puch had sent screenshots revealing her relationship with Cedillos-Campos to his girlfriend. Police had previously said Puch and Cedillos-Campos were co-workers and had an intimate relationship. The witness said Cedillos-Campos became angry after learning about the screenshots and said he intended to kill Puch. That account added a potential explanation for the killing that police had not publicly identified in the first days of the investigation.

The same witness described what allegedly happened at the restaurant before Puch’s death. According to the complaint and police accounts, Cedillos-Campos left with a fixed-blade knife from the business, black latex gloves and a water bottle. Fairfax County Police Chief Kevin Davis later said investigators had surveillance footage showing him taking those items. Authorities said Cedillos-Campos then obtained gasoline from his motorcycle and placed it in the bottle. Police presented those actions as evidence that the encounter with Puch was planned rather than spontaneous, although the precise legal significance of the evidence would be decided through the court process.

Telephone evidence also became part of the investigative timeline. The witness told police that a call between Puch and Cedillos-Campos was overheard at about 1:30 a.m., when the two allegedly arranged to meet. FOX 5 reported that police documents said call records corroborated an early-morning conversation. Authorities said the two then met at the parking area for Difficult Run Park in Great Falls, roughly a short drive from the Herndon restaurant. Police have not publicly described everything said during that call or established in the reports reviewed for this article why Puch agreed to meet him there.

Investigators allege that Puch was attacked after the meeting. Fairfax County police said she was stabbed multiple times and gasoline was poured on her. Authorities further alleged that Cedillos-Campos tried unsuccessfully to ignite the gasoline. The county police department’s Aug. 19 announcement confirmed that detectives had determined Puch suffered multiple stab wounds and that gasoline had been poured on her. Later reporting on police documents said a preliminary autopsy found that Puch died from multiple sharp-force injuries and classified the death as a homicide. The details were reported in restrained terms by authorities because of the violent nature of the killing.

Another part of the case comes from what the witness said happened afterward. At about 4 a.m., according to reports on the criminal complaint, Cedillos-Campos allegedly called the witness and said that “he did it” before ending the call. The witness understood the statement as referring to Puch. Investigators later found black latex gloves and an empty water bottle with an odor of gasoline, according to FOX 5’s account of the police documents. Authorities also said gasoline could be smelled on or near Puch. Those findings, combined with the restaurant footage and call records, became central to the police reconstruction of the night’s events.

The investigation began in public several hours later. Fairfax County police said officers were dispatched at 6:43 a.m. after an unconscious woman was reported in the Difficult Run Park parking lot in the 8800 block of Georgetown Pike. Puch was found near a 2011 Honda Civic registered to her and was pronounced dead at the scene. Local reports said a person arriving to exercise had discovered her. Homicide detectives and crime-scene personnel took over the case, processed the vehicle and surrounding area, sought surveillance footage and appealed for information before announcing a suspect’s arrest two days later.

Police said detectives identified Cedillos-Campos during that 48-hour period and worked with authorities in Maryland to locate him. Fairfax County’s Fugitive Tracking and Apprehension Team coordinated with Prince George’s County police and the U.S. Marshals Service, and Cedillos-Campos was arrested in Lanham, Maryland, on Aug. 19. He was initially held in Prince George’s County while awaiting transfer to Virginia. Fairfax County police announced that he faced second-degree murder, while Davis said at an Aug. 19 news conference that investigators and prosecutors would continue evaluating the evidence. He said the available facts appeared to him to show planning, but any additional or amended charge would require a formal prosecutorial decision.

Police also said Cedillos-Campos spoke with detectives after his arrest. Davis told reporters at the time that the 19-year-old was offering investigators what the chief characterized as a full confession. That statement is part of the prosecution’s investigative account and is not equivalent to a guilty plea or a court finding. The publicly available reports reviewed for this article did not establish the complete circumstances of the interview, whether defense lawyers have challenged any statement attributed to Cedillos-Campos, or what evidence might ultimately be admitted if the case proceeds to trial.

Puch’s death left a young child without her mother. Police officials described Puch as a mother of a 3-year-old girl and emphasized that detectives were working with victim-services personnel to assist her family. That personal loss sits behind a case that has otherwise been described largely through surveillance footage, records and forensic evidence. The later disclosure about the screenshots provided investigators with a possible motive, but motive is only one part of the criminal case. Prosecutors would still have to prove every required element of any murder charge beyond a reasonable doubt if the case is contested.

Cedillos-Campos had been charged with second-degree murder in Puch’s death. Public reports reviewed through Oct. 19 did not establish a later plea, trial outcome or final disposition, and no change in the murder charge could be independently confirmed. The account contained in the criminal complaint, including the witness’s description of the screenshots and alleged threat, remains an allegation that would be subject to challenge in court.

Author note: Last updated October 19, 2026.