In 2009 he lied to a Glendale, Arizona police officer about his identity when that officer was investigating an assault outside a bar where he was a customer. He was disciplined for this deceit. In 2020 he was one of 100 Phoenix police officers on the department's "Brady list",
On July 30, 2021, Dizdar phoned 9-11, to report his date Angela Tramonte had gone missing when he took her on an expedition on a challenging desert hike to the top of Camelback Mountain. Tramonte had met Dizdar online, and traveled from the Boston area to meet him for the first time, that very day. Dizdar was an experienced desert hiker. Tramonte had never hiked the high desert before. Dizdar had failed to make sure they had a supply of water for the hike. When Tramonte said she wasn't feeling well Dizdar abandoned her, telling her to make her own way back to his car, while he continued to the top of the peak.
When he returned to the parking area he could not find her, so he phoned 9-11. Her body was found, three hours later. She had died of heat exhaustion.
The coroner's office ruled Tramonte's death an accident, in spite of widespread criticism of Dizdar's role.
- Patrick Reilly (2021-08-29). "Woman’s death on first date hike with cop ruled accidental". New York Post. Archived from the original on 2021-08-31. https://web.archive.org/web/20210831195244/https://nypost.com/2021/08/29/angela-tramontes-death-on-arizona-hike-with-phoenix-cop-dario-dizdar-ruled-accidental/. Retrieved 2021-09-01. "Dizdar has lied to police before, according to KNXV. He was among a group of 100-plus Phoenix officers who were named in December as being listed in the Maricopa County Attorney’s Office’s 'Brady list,' which tracks law enforcement officials with alleged integrity concerns, including lying on the job, the station reported."
- Dave Biscobing (2020-12-29). "LIST: 'Brady list' misconduct files for 100+ Phoenix PD staff". ABC 15. Archived from the original on 2021-08-04. https://web.archive.org/web/20210804065739/https://www.abc15.com/news/local-news/investigations/brady-list/list-brady-list-misconduct-files-for-100-phoenix-pd-staff. Retrieved 2021-09-01. "As a result, prosecutors began maintaining “Brady lists” to track law enforcement officials with integrity concerns, including past crimes, lying on the job, and other misconduct."
- "Investigators say officer previously disciplined for dishonesty". KYMA (Phoenix, Arizona). 2021-08-03. Archived from the original on 2021-08-30. https://web.archive.org/web/20210830160559/https://kyma.com/news/top-stories/2021/08/03/update-phoenix-officer-with-history-of-lying-is-last-person-to-see-dead-hiker-alive/. Retrieved 2021-09-01. "According to internal Phoenix Police Department (PPD) documents, in 2020, Dizdar was previously disciplined and placed on a Maricopa County Attorney’s Office “Brady list” which tracks police officers with "integrity concerns" because of past misconduct."
- Ellen Killoran (2021-08-11). "Bachelor Party Hikers Saw Angela Tramonte and Police Officer Date Before She Was Found Dead: ‘It Did Not Appear To Be Amicable’". Crime online. Archived from the original on 2021-08-22. https://web.archive.org/web/20210822033206/https://www.crimeonline.com/2021/08/11/bachelor-party-hikers-saw-angela-tramonte-and-police-officer-date-before-she-was-found-dead-it-did-not-appear-to-be-amicable/. Retrieved 2021-09-01. "Orr said he believes the above photograph was taken at the moment Tramonte decided to turn back, while Dizdar continued toward the summit. Although Orr was too far from the pair to hear their conversation, he said, 'It did not appear to be amicable .. It appeared to be some sort of dispute.'"
- "Arizona Medical Examiner Rules Hiker Angela Tramonte Of Saugus Died From Heat Exposure". Boston CBS (Phoenix, Arizona). 2021-08-30. https://boston.cbslocal.com/2021/08/30/angela-tramonte-arizona-hiker-cause-of-death/. Retrieved 2021-09-01. "The pair went on a hike at Camelback Mountain on July 30 in what was described as intense heat, and police said they did not have any water."
- Johanna Li (2021-08-30). "Death of Angela Tramonte, Who Died Hiking With Cop Previously Disciplined for Lying, Ruled Accidental". Inside Edition. Archived from the original on 2021-08-31. https://web.archive.org/web/20210831070443/https://www.insideedition.com/death-of-angela-tramonte-who-died-hiking-with-cop-previously-disciplined-for-lying-ruled-accidental. Retrieved 2021-09-01. "What added to their suspicion was that Tramonte died less than 24 hours after arriving in the state, and that Dizdar had previously been disciplined by Arizona police for once lying about his identity."
- Scott J. Croteau (2021-08-01). "Boston woman dies while hiking in Arizona, authorities say". Mass live. https://www.masslive.com/boston/2021/08/boston-woman-dies-while-hiking-in-arizona-authorities-say.html. Retrieved 2021-09-01. "'At approximately 4:40pm, after an extensive search, the missing hiker was located off the Echo Canyon Trail, adjacent to a home, on the northeast side of Camelback Mountain,' the department said Friday."
- Cassie McGrath (2021-08-03). "GoFundMe raises more than $42,000 for Angela Tramonte, Saugus woman who died hiking in Arizona". Mass live. https://www.masslive.com/boston/2021/08/gofundme-raises-more-than-42000-for-angela-tramonte-saugus-woman-who-died-hiking-in-arizona.html. Retrieved 2021-09-01. "In a GoFundMe, which has raised more than $42,000 in the span of a day, friends noted Tramonte was fit, always stayed hydrated and would not have gone hiking unprepared. Friends are questioning what happened during the hike that lead to her death."
- "Angela's Resume: Angela Tramonte". Archived from the original on 2021-09-02. https://web.archive.org/web/20210902005610/https://www.exploretalent.com/resume/angelatramonte3/2351877. Retrieved 2021-09-01.
- "Cause of death released for local woman who died during Arizona hike". Boston 25 News (Winthrop, Massachussetts). 2021-08-28. Archived from the original on 2021-08-29. https://web.archive.org/web/20210829002517/https://www.boston25news.com/news/local/cause-death-released-local-woman-who-died-during-arizona-hike/DCFIRWJQR5GRTA63C545FQ3UJA/. Retrieved 2021-09-01. "Angela Tramonte, 31, originally of Saugus, died on July 30 and the primary cause of death was environmental heat exposure, according to the Maricopa County Office of the Medical Examiner in Arizona. The manner of death was accident."
- Dred Karedes (2021-08-30). "‘I have to fight for her’: Mom of Saugus native who died during first date with AZ cop speaks out". Boston 25 News (Saugus, Massachussetts). Archived from the original on 2021-08-31. https://web.archive.org/web/20210831030913/https://www.boston25news.com/news/i-have-fight-her-mom-saugus-native-who-died-during-first-date-with-az-cop-speaks-out/JRDOVDA72JAS7PZ5L62DI4MW2I/. Retrieved 2021-09-01. "Nancy Tramonte told Boston 25 News she still has many suspicions about what happened despite a preliminary autopsy report that was released over the weekend."
- Emma Colton (2021-08-05). "Police officer who took date on hike before she was found dead was previously disciplined for lying to police". Fox News. Archived from the original on 2021-08-31. https://web.archive.org/web/20210831085855/https://www.foxnews.com/us/phoenix-police-officer-disciplined-lying-hiker-dead. Retrieved 2021-09-01. "Phoenix Police Officer Dario Dizdar has been with the force since 2007, and was disciplined in 2009 for lying to Arizona police about his name and age during a criminal investigation, according to internal affairs documents reviewed by The Daily Beast."