The candidate was shot in Obregon City, where he was handing out flyers ahead of the June 6 regional elections. A young woman who was part of his campaign team was also wounded.
Murrieta, who headed Sonora's Attorney General Office for nine years, was contesting the Cajeme's mayor post.
His murder was condemned by Governor Claudia Pavlovich, the National Regeneration Movement (Morena) candidate for Sonora governorship Alfonso Durazo, and "It Goes for Sonora" alliance representative Ernesto Borrego.
An infographic of the political violence so far this year in Mexico. Another murder of a woman PAN candidate in the PRI stronghold of Oaxaca yesterday makes 11 so far this cycle. pic.twitter.com/BJpOutzzWS
The Citizen Security and Protection Secretariat reported 64 Mexican politicians murdered since September 2020 ahead of parliamentary and regional elections. At least four assassinations have taken place in Sonora.
In March, the MC representative Ricardo Bours announced that his party would not present candidates in some municipalities located in the Sonora highlands due to threats from organized crime gangs.
Chihuahua, Sonora, San Luis Potosi, Michoacan, Sinaloa, and Guerrero are the Mexican states where electoral candidates' lives face greater risks due to political violence.