A Sinaloa state official who was not authorized to be quoted by name said that armed men stopped Hugo Castellanos in a vehicle he was travelling in and kidnapped him.
They apparently let his companions go and then killed him. Castellanos' body was found Sunday in a stolen vehicle, along with cash and documents, in the Sinaloa state capital of Culiacan.
The area is known for its drug trade and drug capos have been known to bribe or pressure pageants to award titles to their girlfriends.
According to local media, Castellanos had attended a Miss Sinaloa pageant before he was kidnapped and killed. And in southern Mexico, meanwhile, prosecutors said five men died late Monday in a hail of bullets outside a bar near the Guerrero state capital of Chilpancingo.
A total of 123 shell casings from assault rifles were found at the scene of the shootings.
Prosecutors said the motive in the attack is still under investigation. The area is known for drug violence and the cultivation of opium poppies.