MIDLAND, TX – A Texas man received a 35-year prison sentence Friday after pleading guilty to murdering his ex-girlfriend and concealing her body following their breakup in 2023.
Mario Juan Chacon, 27, pleaded guilty to murder and tampering with evidence in the death of 20-year-old Madeline Pantoja, according to the Midland County District Attorney’s Office. Judge David G. Rogers of the 142nd District Court sentenced Chacon to 35 years for murder and 20 years for tampering with evidence, with both sentences running concurrently.
Pantoja disappeared on May 10, 2023, after friends said she made plans to go swimming at their apartment complex the following day. When she failed to respond to calls and messages, concerned friends went to her unit at the Palladium Museum Place Apartments on West Francis Avenue but received no answer.
Midland Police officers conducted welfare checks on May 11 and May 12, 2023, after requests from Pantoja’s brother and another caller who reported hearing a woman’s voice inside the apartment. When officers finally gained entry on May 12, they found the apartment empty but discovered suspicious evidence.
Inside the residence, police found a mop and dirty bucket near the front door, with floors that were “extremely sticky as it is when too much cleaning product is used,” according to court documents. Pantoja’s coffee table was missing, her dog had been left without food or water, and there were holes in bathroom and bedroom doors with hair attached. A large red stain was visible on bedsheets, and the comforter was gone.
Chacon initially told police he last saw Pantoja on May 9 and spoke with her by phone on May 10 while he was at home. In a second interview, he changed his story, claiming he had forgotten to mention meeting with a cousin who lived in Pantoja’s apartment complex that night.
Surveillance footage contradicted Chacon’s timeline. Traffic cameras, private security footage, and cellphone location data tracked his movements between 12:26 a.m. and 3:37 a.m. on the night Pantoja disappeared. Oil company footage showed his pickup truck near the apartment complex just before 2 a.m., despite his claims of leaving before 11 p.m.
Using AT&T records and Texas Rangers assistance, investigators searched areas near East County Road 190 and South County Road 1138 in Midland County on May 20, 2023. Human remains identified as Pantoja were discovered, with a source close to the investigation telling local media the body was found inside her missing coffee table.
A Dallas County autopsy determined Pantoja died from strangulation and suffocation during an attack that also included being beaten with hands and at least one object. Chacon was arrested and charged the same day the remains were found.
Chacon was formally indicted for murder on July 19, 2023, and for tampering with evidence on November 19, 2025. He had remained in Midland County Jail on $3 million bond since his arrest and will be transferred to the Texas Department of Corrections. He becomes eligible for parole after serving at least half his sentence.
