Mexican peace activists and bloggers who try to warn fellow citizens about drug violence say they feel under attack following the kidnapping and possible killing of one of their colleagues.

The kidnapping of Dr. Maria del Rosario Fuentes Rubio has sent a chill through the border state of Tamaulipas.

The few who dare speak out in the home turf of violent drug gangs say they will carry on, but acknowledge the situation has grown more difficult.

On Wednesday, someone hacked Fuentes Rubio's Twitter account, @Miut3. The hacked account showed a photo of Fuentes Rubio's bloody face and the words "today my life has reached its end." It warned others to close their accounts.

Social media users in Mexico who comment on cartel violence have been killed in the past.