Sonoran authorities say they’ve arrested and charged a suspect in the murder of a well-known Yaqui activist.

Tomás Rojo went missing in late May, and his body was found and identified last month. Now a 26-year-old man is in custody and facing charges of premeditated murder and criminal association, according to the state Attorney’s Office.

Authorities claim the motive may have been related to informal tolls set up along the interstate that runs through Yaqui territory in Sonora. Rojo had been pushing for one that would directly benefit Yaqui people, while authorities say criminal groups have tried to illegally profit from them.