MIAMI -- Politicians are being targeted in Mexico ahead of the country's July elections, and the latest murder was caught on surveillance video.
The footage shows Mexican congressional candidate Fernando Puron posing for a selfie with a supporter after a campaign debate last Friday, when a man walks up from behind, raises a gun and fires at the back of his head.
Puron was running on an anti-cartel platform which made him a target in Piedras Negras, which borders Texas.
CBS News spoke to the current mayor of Piedras Negras, Sonia Villarreal, who says her life was threatened just one day earlier.
Last summer, for "CBSN: On Assignment," CBS News reported Mexico had become the most dangerous country in the western hemisphere for reporters.