21 June 2011 Last updated at 04:03 ET

Gunmen in Mexico kill crime journalist Lopez Velasco

Notiver called for a swift investigation to catch those behind the murders

A Mexican journalist has been shot dead, along with his wife and 21-year-old son, by gunmen who burst into his home.

Miguel Angel Lopez Velasco, who wrote about politics and crime, was killed in his house in the port city of Veracruz.

Authorities have not yet determined a motive for the murders, which they condemned as a "cowardly" attack.

Rights groups rank Mexico as one of the most dangerous countries in the Americas for journalists.

Armed men broke into Mr Lopez Velasco's house in Veracruz early on Monday morning, killing him, his wife Agustina and his son, Misael.

Mr Lopez Velasco, 55, wrote for the daily newspaper Notiver, where he was also an editor. His columns focussed on crime, drug trafficking and political corruption.

In its coverage, Notiver called for a swift and transparent investigation to find those guilty of the three killings.

Those responsible "should be punished with the full weight of the law", the newspaper said.

In a statement on Monday, Mexico's National Commission on Human Rights said that, since 2000, 70 journalists had been killed and 13 were missing. There have also been 22 attacks on media organisations.