A journalist was gunned down this week as he left a holiday party in the Mexican Caribbean resort town of Tulum, human rights officials and an international media group said Friday, bringing to 12 the number of reporters killed this year in the country. Alberto Velazquez, who worked for the newspaper Expresiones de Tulum, was killed on Tuesday. According to the Committee to Protect Journalists, Velazquez had written articles critical of local officials, and his paper had received threats. In a statement, the group quoted colleagues as saying Velazquez was shot by a gunman on a motorcycle, and they believed it was related to his reporting. Tulum, a beach town about 80 miles (129 kilometers) south of Cancun, draws a lot of tourists from the popular resort city because of its coastal Mayan ruins. The CPJ said at least 17 reporters have been murdered in Mexico since 1992 in direct reprisal for their work. It did not specifically include Velazquez in that group, but urged a thorough investigation. "Mexico has become a high-risk country for journalistic work," the country's National Human Rights Commission wrote, noting that in all, 57 reporters have been killed since 2000 and another eight are missing. Attacks on journalists - including killings, explosives tossed at newspaper offices, beatings and other forms of harassment - have risen over the course of the decade, according to the commission, from 13 in 2000 to 78 this year. The rights commission, which can only issue nonbinding recommendations, demanded that authorities in the Caribbean state of Quintana Roo investigate Velazquez's killing.