Mexico City: Mexican authorities detained on Thursday seven federal police officers accused of committing extortion in the border city of Matamoros, days after 13 other agents were held in a kidnapping case.
The agency`s internal affairs department was investigating the kidnapping case when it received a separate extortion complaint from another person, leading to the new arrests, a federal official said.
"Internal affairs will continue the investigation of the two cases to find out if there are more involved in order to root out criminal acts" in the police force, the official said.
On Sunday, 13 federal police officers were taken into custody and face charges over kidnapping a businessman in Matamoros, a crime-riddled city that lies across from Brownsville, Texas. The man was released and found on a highway following the abduction.
The administration of President Enrique Pena Nieto has faced a series of scandals involving security forces.
Soldiers were accused of summarily executing gang suspects in central Mexico last year.
In September, municipal police in southern Guerrero state abducted 43 college students and delivered them to a drug gang, which slaughtered the group, according to prosecutors.
Matamoros, meanwhile, has been hit by a surge of drug cartel violence this year that has terrorized the population.
On Sunday, unidentified gunmen opened fire on the convoy of Mayor Leticia Salazar, who escaped unscathed.
Matamoros is known as a bastion of the Gulf cartel, whose internal battles have been blamed for the recent violence in the city and the rest of Tamaulipas state.
Pena Nieto deployed extra federal forces to the state last year to counter a spasm of gang violence.