A Mexican prosecutor said beauty queen Maria Susana Flores Gamez fired at army soldiers before she was killed in an armed clash last month in the northwestern state of Sinaloa.
The delegate of the federal Attorney General's Office in Sinaloa, Enrique Feregrino Taboada, told reporters Tuesday that a gunshot residue examination conducted on the 22-year-old woman's body turned up positive.
He said the investigation was continuing into four people detained in the wake of the Nov. 24 clash, which took place in the town of Mocorito and pitted the soldiers against a cell of the Sinaloa cartel.
The shootout occurred when the troops came under fire by a group armed assailants while patrolling the area and repelled the aggression.
Two soldiers and a civilian who was driving in the area at the time of the shootout also died in the exchange of gunfire.
A man identified as Orzo Ivan Gastelum, suspected leader of the criminal cell and apparently Flores' boyfriend, managed to escape during the firefight.
Authorities conducted the sodium rhodizonate test - used to detect the presence of gunshot residue - on the young woman after an AK-47 rifle was found next to her body following the shootout.
Flores won the Sinaloa Woman contest and competed in the Our Sinaloa Beauty contest, which she did not win.
This is not the first time that a Mexican beauty queen has been linked to drug traffickers.
Laura Elena Zuñiga, who won Our Sinaloa Beauty in 2008, was arrested along with seven men on firearms and money laundering charges on Dec. 23, 2008, in Zapopan, a city in the western state of Jalisco.
The beauty queen was released a few weeks later because prosecutors could not find sufficient evidence to put her on trial.
Zuñiga's story inspired director Gerardo Naranjo's 2011 film "Miss Bala."
Journalist and writer Javier Valdez told Efe in an interview late last month that links between drug kingpins and beauty queens are a constant in Mexico, noting that young women are sought out by criminals in schools and on the street.
Sinaloa is home to the drug cartel led by notorious fugitive Joaquin "El Chapo" (Shorty) Guzman, but other criminal organizations, including the Los Zetas and Beltran Leyva cartels, also operate in the area.
The Sinaloa cartel, sometimes referred to by officials as the Pacific cartel, is the oldest drug mob in Mexico. EFE