A total of 19 people were arrested in connection with the murder earlier this month of a mayor in the western Mexican state of Michoacan, the government said Monday.
Tanhuato Mayor Gustavo Garibay, a member of the conservative National Action Party, or PAN, was gunned down as he left his house on March 22.
"The material and intellectual authors" of the murder have been arrested, special commissioner for Michoacan state Alfredo Castillo said in a Twitter post.
The firearms used to commit the murder were found in the possession of the suspects, Castillo said without discussing the possible motive for the killing.
Garibay was almost murdered in October 2012, while Tanhuato city government secretary-general Jose Pedro Cordoba Aguirre was killed in February 2013, PAN officials said.
The federal government deployed soldiers and police in Michoacan on Jan. 13 in an effort to end the wave of drug-related violence in the state, where civilians began arming themselves to fight the gang last year.
The federal government has named high-level officials, such as Castillo, to posts in an effort to provide support to the state government. EFE