Story highlights Maria Santos Gorrostieta was fearless in the face of assassination attempts

She was hailed for her bravery, but was found dead last week

A report says the local drug trade called the shots in her town of Tiquicheo

Investigators aren't ruling out any possible motives -- political, personal or criminal

The first time an assassin's bullet tried to find her, Maria Santos Gorrostieta escaped, but her husband was killed.

That was in 2009, when she was mayor of Tiquicheo, a small town in the Mexican state of Michoacan, which has seen some of the most brutal drug-related violence.

The bullets found her in January of 2010, but again, she survived.

She remained defiant, lifting her shirt at one point to show reporters her bullet wounds and scars after the second attack.

Gorrostieta finished her term as mayor in 2011 and remarried.

But the forces who wanted her dead prevailed this month, kidnapping her while she drove her daughter to school.

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Gorrostieta's body was found last week, her hands bound. No bullets this time.

Investigators said there was evidence of a blow to the back of the head.

It was a shocking end to a public servant who vowed to put her small town's interests first while she held a position that many try to influence.

"I will rise up again as many times as God allows me to so that I can keep on seeking, fighting for, and working out plans, projects and actions for the benefit of the people, especially those most in need," Gorrostieta, who was also a medical doctor, said after one of the unsuccessful attacks against her.

Michoacan is the scene of a turf war between rival drug cartels, and smaller organized crime groups operate there as well.

In 2009, she spoke about the importance of entrusting the mayor's office to a woman.

"The most important thing is not to be afraid," she said then, gaining a reputation for civic-mindedness.

Stories of heroes and villains constantly emerge from Mexico, where acts of bravery and savagery coexist in the midst of a plague of drug violence.

Gorrostieta's story appears to fall easily within the heroic category, though a report published Tuesday in the leading newspaper El Universal is a reminder that the most accurate tales often include shades of gray.

Even though a majority of Mexico is safe from drug violence, the newspaper described Gorrostieta's city of Tiquicheo as one where the local drug trade called the shots and, citing unnamed sources, may have factored in its politics.

Investigators are not ruling out any possible motives -- political, personal or criminal -- in her killing, the state's deputy attorney general, Marco Aguilera, told CNN.

The investigation is focusing on reconstructing the 11 months of Gorrostieta's life since leaving office and whether there is anything that indicates impending danger.

The former mayor did not reach out to authorities to seek protection or to report threats at any time, Aguilera said.

The deputy attorney general said that her first husband, Jose Sanchez, had been the target of a failed assassination attempt before the first attack against his wife, in which Sanchez died. Between them, the couple was targeted a total of four times, and a motive for the attacks was never established, Aguilera said.