The Maricopa County Sheriff's Office says a maximum security prisoner arrested for plotting to kill another inmate also hoped to assassinate Sheriff Joe Arpaio. 

Detectives arrested 29-year-old Samuel Matta Wednesday, an inmate in the state prison in Florence. Matta and two other inmates from Sheriff Arpaio's Fourth Avenue Jail are charged with conspiring to kill a fellow prisoner.

Detectives were first tipped off that Matta was planning to publicly assassinate Arpaio using a high-powered rifle. Authorities say Matta believed Arpaio to be personally responsible for the deportation of some of his family members to Mexico from their home in El Mirage.

The investigation into the Arpaio murder plot then led authorities to the plan to kill another inmate.