Puron stood outside the building of a state university with a woman who asked him for a photo when a killer approached him from behind, fired a shot at the back of the head and fled the scene, El Universal newspaper reported, publishing a CCTV video of the incident.
Puron was nominated to the elections, which will be held on July 1, from the ruling Institutional Revolutionary Party.
According to analytical company Etellekt, 112 politicians and candidates all over the country were assassinated during the electoral campaign, as of June 9. Of those killed, 28 were people preparing to become candidates for elective posts, and 14 were already registered candidates.
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