MEXICO CITY (Reuters) - An ex-member of an informal police force running for Mexico’s Senate is battling attacks labeling her a “kidnapper,” drawing attention to radical proposals by her ally, presidential candidate Andres Manuel Lopez Obrador, to end the drug war.

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Nestora Salgado, who once ran a local community police force in the opium-rich southwestern state of Guerrero, said she had filed a lawsuit accusing ruling party presidential candidate Jose Antonio Meade of defamation after he called her a “kidnapper” in a televised debate.

The fight over whether Salgado is a heroic social activist or a criminal has put a spotlight on wider differences between presidential candidates over how to fix Mexico’s law and order problems, a major campaign theme ahead of the July 1 election.

Meade, third placed in polls, kept up pressure against his rival and Salgado in a Tweet on Friday, writing that as president he would follow the law without exception “while others opt for amnesty and form alliances with criminals.”

Lopez Obrador is exploring a plan for criminal amnesty to quell the country’s gang-related violence, on the heels of the bloodiest year in a war against drug gangs that has tallied up at least 200,000 homicides over the past decade.

The amnesty idea, along with his backing of Salgado and Jose Manuel Mireles Valverde, a former vigilante leader in the gang-terrorized state of Michoacan, is an attempt to secure votes from indigenous and other marginalized groups drawn into the drug war, said Javier Oliva Posada, a political science professor at the National Autonomous University of Mexico.

Salgado, 46, helped found her local policing group after witnessing the kidnapping and murder of a young taxi driver in 2012, part of the “autodefensa,” or self-defense, movement that grew a few years ago in towns with little trust in either armed drug gangs or the police forces sent to fight them.

Salgado’s group was considered legal under a Guerrero state law allowing self-policing in certain cases.

In 2013, Salgado, a dual U.S.-Mexico citizen, was arrested after the families of six teenage girls locally accused of dealing drugs said her group had kidnapped and extorted them.

Salgado spent two years and seven months in prison but a federal judge in 2016 acquitted her of all charges.

In a 2016 report, Mexico’s National Human Rights Commission said that Salgado’s arrest violated her right to due process. But the entity also recognized that 12 prisoners, including four minors, in Salgado’s town of Olinala had experienced human right violations at the hands of community police groups.

Lopez Obrador has said Meade’s attacks are a “dirty war.”

“She is fighting for there to be peace and tranquility and was accused in a despicable way,” Lopez Obrador said at a campaign rally in the central state of Jalisco this week.

Salgado has maintained her innocence.

“In the two years that I’ve been free, the campaign now attacking me hasn’t made a single sound,” she said in a radio interview on Thursday. “Now that I am a running candidate, they want to make me wear the mask of a criminal.”