Updated

Miguel Angel Jimenez, a political activist who played a prominent early role in the search for 43 students and other missing people in southern Mexico, was killed over the weekend, an associate said Monday.

The bullet-ridden body of Jimenez, a member of the Union of Towns and Organizations, or UPOEG for its initials in Spanish, was found in a car near a town where he had helped found a community police program.

UPOEG leader Bruno Placido confirmed the death and said Jimenez had received threats related to his search efforts.

Jimenez began organizing searches for 43 teachers' college students who went missing after they were detained by police last September in Guerrero state.

Prosecutors say corrupt local police in the city of Iguala turned the students over to members of a drug cartel, the Guerreros Unidos, who killed the students and incinerated their bodies.

But the searches Jimenez led into the mountains surrounding the city turned up clandestine graves filled with other bodies.

Placido said the death threats may have come from Guerreros Unidos and Jimenez had returned to his hometown of Xaltianguis in Guerrero to be safer.

Jimenez was found dead on the outskirts of Xaltianguis, and relatives buried him there Sunday.

Jimenez played a key role in expanding the search effort to include hundreds of other Iguala residents whose relatives disappeared during the cartel's reign of kidnappings and killings.

While he gradually relinquished leadership of the search efforts after November, he continued to supply information and said he had new leads.

"He was always looking for somebody to help," said Xitlali Miranda, one of the activists in the Iguala searches. "He was one of the first people to say, 'If these aren't the students (bodies), then who are they?'"

In July, Mexico's attorney general's office confirmed that at least 60 clandestine graves with 129 bodies have been found so far on the outskirts of Iguala. Most of the bodies remain unidentified.

Jimenez also organized community police efforts to fight kidnappings, killings and extortion by criminal gangs, and drives to document vote fraud in June's midterm elections.

In an April interview with Kara Andrade, a doctoral student at American University, Jimenez said he had received death threats from "people who are involved in things and whose interests I have impacted."

"They've chased me, in my town (Xaltianguis) they've tailed and followed me from place to place," Jimenez said.

Still he kept up his activism in Guerrero, a state plagued by drug trafficking and cultivation, gang battles, extortion, illegal logging and land disputes.

"I don't do this because of me or the abuses we live now. I do this for the next generation and for my children," Jimenez said. "If someone doesn't sacrifice themselves right now, I ask myself who will?"