Mexican authorities said on Tuesday they had detained a gang of 18 suspected kidnappers - the majority of whom were members of the federal police - in the Pacific resort of Acapulco.
The Mexican government's national security spokesman, Eduardo Sanchez, said 13 of the 18 men aged between 22 and 32 years old were federal police. The gang is thought to be involved with seven murders and four kidnappings, Sanchez said.
The suspects were seized on the outskirts of Acapulco by fellow federal police officers after an anonymous tip, Sanchez said in a press conference.
The tourist resort of Acapulco, which lies in the western state of Guerrero, has been hit by a wave of violence in recent years and is now one of Mexico's most violent cities with a murder rate of 77 homicides per 100,000 people.
The federal police have suffered severe blows to their reputation in recent years following various high-profile embarrassments.
In June last year, a shootout between federal police and corrupt officers at Mexico City's airport killed three officers. Just a few months later, 14 federal police were charged with attempted murder for opening fire on a car carrying two CIA agents outside Mexico City.
Roughly 80,000 people have died in drug-related killings in Mexico since 2007 when former president Felipe Calderon sent in the army to tame the warring cartels.
President Enrique Pena Nieto, who took office in December, has vowed to break with the policies of his predecessor and end the blood-letting by targeting crimes such as kidnapping and extortion.
But kidnapping and extortion have remained high since he took office and critics have called into question how different Pena Nieto's policies are from Calderon's.
Guerrero is one of the most dangerous states in the country, and with 86 reported cases, it has seen more kidnappings in the first eight months of this year than in the whole of both 2012 and 2011, according to federal data.