A Mexican citizen journalist who was actively standing up to the Zeta and Gulf drug cartels was allegedly murdered by them.

Maria del Rosario Fuentes Rubio used her social media account to expose local gang violence, but the gangsters tracked her down and posted her dead body on her own Twitter account, The Mirror reported.

What she was doing was not that uncommon, since the crimes are rarely reported in mainstream media. Residents turn to social media for information on crime in the Mexican state of Tamaulipas -- where extortion, shootouts, kidnappings and executions are rife, the Mirror reported.

But what Rubio did that separated her from the number of residents interested in reporting the crimes was to form a large following on a citizen news site.

She helped create Valor por Tamaulipas (Bravery for Tamaulipas), which had more than 510,000 Facebook fans and 100,000 Twitter followers.

The site posted photos of crimes, missing persons and identified cartel members, under her pseudonym Felina (Catwoman).

The tone of her posts changed on Oct. 16, when she had been tracked down and identified by cartel members, the Mirror reported.

Reporters without Borders said that seven journalists like her have been killed in the past two years.

The New York Daily News reported the last posting from her Twitter account showed two images of Rubio -- one alive and looking at the camera, the other of her dead on the floor.

A message that was allegedly posted by the cartel members warned others against speaking out.

The message translates to, "Friends and family, my real name is Maria del Rosario Fuentes Rubio, I am a doctor, today my life has come to an end."

A second tweet warned others, "Shut down your accounts, do not risk your families' lives as I have done. I ask your forgiveness."

The founder of the Valor por Tamaulipas site remains unidentified, but a post on the site countered the warning by the cartel members by saying that Rubio did not back down and others shouldn't either.

Rubio's social media account has been suspended, according to Twitter, but the final post is still on other users' sites.