A photojournalist who had received threats over his work in the northern Mexican state of San Luis Potosi has been found dead, the government said Friday, a day after he was kidnapped.

The federal Mechanism to Protect Journalists and Rights Activists called for an "immediate and effective investigation" into the killing of Edgar Daniel Esqueda, who was reportedly kidnapped Thursday by gunmen disguised as police officers.

He is at least the 11th journalist killed so far this year in Mexico, which rights groups say drug wars and corruption have made one of the most dangerous countries in the world for the press.

Local media reported that Esqueda's body was found dumped by the San Luis Potosi airport, bound and bearing signs of torture.

The federal protection program said Esqueda, who worked for several local news websites, had recently reported that state police had threatened and harassed him while he was working.

He told authorities that five police officers threatened to beat him up and take his camera while he photographed the scene of a shootout on July 4, forcing him to delete his photos.

Nine days later, police reportedly harassed him again while he was working, saying they "would be watching him" because they suspected he was "passing information to the bad guys," the federal program said in a statement.

The federal protection program had asked local authorities to grant Esqueda protective measures, but it is unclear whether he was ever given any of the measures offered by the program, such as security cameras, panic buttons and bodyguards.

Investigators have denied that Esqueda was kidnapped by police, saying the gunmen who hauled him from his home on Thursday morning were criminals disguised as police officers.

Colleagues of the slain photojournalist protested in San Luis Potosi, the state capital, after his body was found, placing their cameras on the ground atop handwritten signs reading "Enough already" and "Justice."

Rights groups say at least 11 journalists have been killed in Mexico so far this year, though it is unclear whether they were all targeted because of their work.

Since 2000, more than 100 journalists have been murdered in Mexico. More than 90 percent of the crimes remain unpunished.

Source: AFP