A Mexican community activist who helped families search for their missing relatives has been killed.
Miguel Angel Jimenez Blanco's body was found near his home in a town in the south-western state of Guerrero.
He had led search parties after the disappearance of 43 students in the nearby town of Iguala last year threw light on hundreds of other missing people.
Guerrero is a region plagued by gang and drug violence.
At least 15 people were killed there over the weekend.
Mr Jimenez Blanco's body was found in the taxi he owned in the small town of Xaltianguis.
He had been part of an organisation which had supported the search for the students in the hills around Iguala. He had also helped dig up a number of graves of murdered people that were found during the search for the students.
He had helped organise a group called The Other Disappeared, mostly women who meet every Sunday to search the hills for the remains of their loved ones.
'This area is a cemetery'
The search parties started in November last year, a few months after the 43 students were abducted and presumably killed in Iguala on 26 September.
Since the group began work, it has found 129 bodies, which were handed over to the authorities for identification.
In a BBC interview, Mr Jimenez Blanco said that after Iguala, 300 families had come forward saying they had missing relatives too.
"We have been saying from the start that this area is a cemetery," he said at the time.
David Cienfuegos, government secretary of the state of Guerrero, told the BBC that many families had stayed silent for decades for fear of retribution.
"Many crimes linked to the disappearance of people need a statement to the police so the case can be taken up.
"In the last decade in Guerrero there have been few statements taken because the families are afraid. They fear the police themselves are involved in the disappearances."
In an interview with the Los Angeles Times, one of Mr Jimenez Blanco's friends, Mario Vergara, whose brother went missing last year, said that he motivated hundreds of families.
"He taught us how to search and how to push and every day he would give us the energy to carry on."
The case of the missing 43 students promoted a national and international outcry. The parents of the students and many other Mexicans still reject the government's version of events.
The administration of President Enrique Pena Nieto has insisted the students were killed by gang members on the orders of corrupt local police.
The bodies were then burnt, and the remains dumped in a river, but so far only one student has been identified.
The case highlighted hundreds of other people missing in Guerrero - Mexico's most violent state.
Guerrero is a major opium-producing state and a battleground for a number of different criminal gangs.
More than 20,000 people are missing across the whole country.