MEXICO CITY (Reuters) - Armed gunmen shot and killed a prominent Mexican activist dedicated to searching for “disappeared” persons in the violent northern state of Tamaulipas, authorities said on Thursday.

Miriam Rodriguez died en route to the hospital after being shot multiple times on Wednesday - Mother’s Day in Mexico - at her home in drug gang-ravaged Tamaulipas.

Mexico’s National Human Rights Commission (CNDH) condemned the murder, saying it underscored the government’s failure to keep the public safe and prevent rights violations of people working as human rights advocates.

After her daughter went missing in 2014, Rodriguez began a search and eventually found her remains in the Tamaulipas town of San Fernando, according to the Comunidad Ciudadana en Busqueda de Desaparecidos en Tamaulipas, a local civic society group committed to searching for the disappeared.

Months later she warned authorities about the perpetrators of the crime, the group said in a statement.

Tamaulipas Attorney General Irving Barrios said the state had been protecting Rodriguez, sending police patrols three times a day to her house. Barrios also said nine people had been put on trial for her daughter’s kidnapping and murder.

The number of people in Mexico disappearing under suspicious circumstances, often related to drug violence, rose to 30,000 by the end of 2016, with Tamaulipas registering 5,563 missing, the highest state total, according to the CNDH.

Comunidad Ciudadana called on the United Nations and the InterAmerican Human Rights Commission to come to the aid of activists and human rights defenders in Tamaulipas as the state and federal government had been unable to protect them.

Well over 100,000 people have died in drug-related violence in Mexico in the past decade.

“Mexico has become a very dangerous place for those who have the courage to devote their lives to search for missing persons,” Erika Guevara Rosas, Amnesty International director for the Americas, said in response to Rodriguez’s murder.

“The nightmare they face not knowing the fate or whereabouts of their relatives and the dangers they face in their work, which they perform given the negligent response from the authorities, is alarming,” Guevara said.