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Left: Mario Juan Chacon (Midland County Sheriff”s Office). Right: Madeline Pantoja (Midland Police Department).
A man from Texas is facing a lengthy prison sentence after being convicted of the violent murder of his ex-girlfriend and attempting to conceal her remains following their breakup, as announced by Texas authorities.
Mario Juan Chacon, aged 27, admitted guilt on Friday to charges of murder and evidence tampering in connection with the 2023 killing of 20-year-old Madeline Pantoja, as reported by the Midland County District Attorney’s Office.
In a swift legal proceeding, Chacon received a 35-year prison sentence for the murder charge and an additional 20-year sentence for tampering with evidence. These sentences will be served concurrently, as determined by Judge David G. Rogers of the 142nd District Court.
The tragic events unfolded on the evening of May 10, 2023, marking the last time Pantoja was heard from. According to an arrest affidavit obtained by Odessa’s NBC affiliate KWES, several witnesses confirmed they had interactions with her that day. Her final message was sent to a friend regarding plans to swim at their apartment complex the following day.
When Pantoja failed to respond to phone calls, concerned friends visited her apartment at the Palladium Museum Place Apartments on West Francis Avenue in Midland, a city situated midway between Fort Worth and El Paso. They received no response at her door.
On May 11, 2023, in response to a welfare check requested by the victim’s brother, Midland Police Department officers were dispatched to the apartment. Again, no one answered the door, according to court documents obtained by the Midland Reporter-Telegram.
On May 12, 2023, someone else who claimed to have heard a woman’s voice coming from inside the apartment called police late in the morning. This time, officers arrived and gained entry but found no one inside. Instead, officers found a mop and a dirty bucket of water near the front door, police said. Inside, the floor was “extremely sticky as it is when too much cleaning product is used when mopping the floor,” according to the arrest affidavit. The woman’s coffee table was also missing. And her dog was left without food or water — which friends said she would never do.
There were also holes in the bathroom door and similar damage to a bedroom door — with hair attached to the latter. The comforter was missing and a large red stain permeated the bedsheet.
The night before, Chacon first spoke with police and said he last saw Pantoja on May 9, 2023, and that he last spoke with her on the phone on May 10, 2023, while he was at home. That story quickly changed.
In a second interview on May 12, 2023, Chacon said he forgot to mention he met up with a cousin the night Pantoja went missing, according to the affidavit. That cousin happened to live in the same apartment complex as Pantoja, the defendant told law enforcement.
Chacon said he dropped his cousin off back at the apartment complex and went home just before 11 p.m. that night, according to police. Footage from a nearby oil company, however, placed the defendant’s pickup truck near the apartment complex just before 2 a.m.
Through a combination of traffic cameras, private surveillance footage, and cellphone location data, law enforcement was able to track Chacon’s movements on the night in question between precisely 12:26 a.m. and 3:37 a.m., authorities claimed. The final camera caught Chacon near South County Road 1160 at 3:22 a.m.
On May 18, 2023, Chacon was interviewed a third time. Detectives told him they “found lies in his timeline.” The defendant, for his part, replied: “OK” and asked to leave; investigators allowed him to do so.
On May 20, 2023, using AT&T records mapped out by Texas Rangers, a search party began combing several miles adjacent to an “approximate one-mile area around East County Road 190 and South County Road 1138 in Midland County,” according to the affidavit. Human remains were found and confirmed to belong to Pantoja based on jewelry, police said. A source close to the investigation told local media the woman’s body was found inside her missing coffee table.
Chacon was arrested and charged later that same day.
An autopsy in Dallas County revealed the victim died from a combination of strangulation and suffocation during an attack that also included being beaten by the defendant using both his hands and at least one object.
On July 19, 2023, Chacon was formally indicted for Pantoja’s murder. On Nov. 19, 2025, he was indicted on the tampering charge.
The defendant has remained in the Midland County Jail on $3 million bond since his arrest. Chacon will soon be transferred to the Texas Department of Corrections, records show. He becomes eligible for parole after he serves at least half of his sentence and will receive credit for time in pretrial detention.