A clash between rival gangs is the most likely explanation for a deadly shooting at a cockfighting event in Mexico, prosecutors say.
Twelve people were killed on Sunday in the incident in the state of Guerrero and another five were injured.
A 12-year-old boy who was watching the event is among the victims.
"All the evidence collected so far indicates the attack was carried out rival criminal groups," said state prosecutor Miguel Angel Godinez.
Those killed - or their relatives - might have had connections to one of the criminal gangs that are active in the region, he told the Radio Red station.
Cockfighting is legal, regulated and quite popular in Mexico.
But Guerrero State Governor Hector Astudillo said the venue where the shooting took place was a clandestine arena.
'Lowest violence levels'
According to witnesses, an armed group stormed the arena and began shooting, aiming at a particular group of spectators.
Among the victims was the event's organiser, Pedro Cano.
Mr Astudillo said that the town of Cuajinicuilapa, where the shooting took place, is in a safe and usually trouble-free area of Guerrero.
"The Costa Chica region is where we had the lowest violence levels in the state," he told Milenio newspaper.
"We could never foreseen something like that happening there."
Army troops have been deployed in the area to reassure the population, said Mr Astudillo.
Mexico's powerful criminal gangs are active in Guerrero, one of the country's most troubled states.
Last year's disappearance of 43 students in the town of Iguala exposed the depth of the problem.