XALAPA, Mexico — Unidentified gunmen shot dead a journalist, his wife and their 21-year-old son after bursting into their home in Veracruz early Monday, the governor of the eastern Mexican state said.

Miguel Angel Lopez was a columnist with the local daily Notiver and wrote frequently about politics and the climate of violence surrounding Mexico's drug wars.

Javier Duarte, the governor of Veracruz, said in a statement that "I don't know how many people went in (to Lopez's house), and there they killed him, his wife and his son. It's a tragedy."

Praising the columnist as a "brave man," Duarte vowed to get to the bottom of the killing.

Since January 2007, 40 journalists have been murdered in Mexico, according to the official National Human Rights Commission. Since 2003, 15 Mexican journalists have disappeared.

In June, a UN report on freedom of expression said Mexico was the most dangerous country for journalists in the western hemisphere.

An estimated 36,000 people have died in drug-related violence since President Felipe Calderon launched an all-out, military-led crackdown on drug cartels shortly after taking office in December 2006.