Investigators obtained DNA from the remains of the parents of Los Zetas cartel boss Heriberto Lazcano Lazcano as part of an effort to confirm that the drug trafficker was killed in a shootout with the security forces earlier this month.
Lazcano, founder and leader of a drug cartel known for its cruelty, died in an Oct. 7 gunfight with marines in the northern state of Coahuila.
The drug lord's body, however, was stolen a day after the shootout.
Investigators obtained DNA samples before the body was taken, but the preliminary identification was made on the basis of fingerprints and information obtained in an examination of the body.
But the height of the man killed in Coahuila was different from that listed on Lazcano's records, raising doubts in Mexican society about whether the government got the right man.
Attorney General's Office investigators dug up the graves of Lazcano's parents on Monday and took DNA samples from one of the bodies, media reports said.
It is not known whether the DNA was taken from the remains of Lazcano's mother or father.
Investigators spent nearly six hours digging in a cemetery in Pachuca, a city in central Mexico, amid tight security.
Genetic samples from the parents' bodies will be compared with those taken from the man thought to be Lazcano before his body was snatched from the morgue by gunmen, officials said.
President Felipe Calderon confirmed earlier this month that the person who died in the gunbattle with marines was the feared Zetas boss, known as "El Lazca."
The Mexican and U.S. governments had offered rewards of $2.3 million and $5 million, respectively, for information leading to the capture of El Lazca.
Lazcano deserted from the Mexican army in 1999 and formed Los Zetas with three other soldiers, all members of an elite special operations unit.
The shootout that killed Lazcano occurred a day after marines captured Zetas regional boss Salvador Alfonso Martinez, who allegedly ordered the killings of more than 300 people, including 72 migrants massacred in 2010 in the northeastern state of Tamaulipas.
After several years as the armed wing of the Gulf cartel, Los Zetas, considered Mexico's most violent criminal organization, went into the drug business on their own account in early 2010 and now control several lucrative territories. EFE