Authorities say 41-year-old Ramon Jimenez of Hanford was initially arrested on December 8 on charges related to a previous domestic violence incident.
Missy was last seen leaving an art show with Jimenez in downtown Fresno on December 7. Investigators said she was his girlfriend.
Friends reported Missy missing the next day when they had not heard from her.
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Officials say Jimenez was involved in a domestic violence incident against Missy last October, and because of this, detectives named him as a person of interest in her disappearance.
A judge held Jimenez in jail without bail for that domestic violence charge while the investigation into Missy's whereabouts continued.
Sheriff's officials say detectives later found "forensic and digital evidence" indicating some sort of violent attack had occurred at Missy's house.
Authorities say they've searched several areas using digital data that gave possible locations of where she might be, but her remains have not been located. However, they say the Fresno County District Attorney's Office is confident it can successfully prosecute this as a murder case.
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Anyone with information that could help with the investigation is asked to call the Fresno County Sheriff's Office.