Summary based on the NamUs case record (MP145611)
Diana Mae Mattingly, age 64, was last seen on December 12, 2020, in Julian, California. She lived in the high desert near Anza-Borrego, specifically at the Butterfield Ranch RV Resort along county Highway S2. Mattingly reportedly suffered from dementia and Alzheimer’s disease, according to her neighbor and caregiver, Lisa Nellom. Nellom had been assisting Mattingly with daily tasks, including attending doctor’s appointments and managing her medications.
In the days leading up to her disappearance, Mattingly had expressed confusion and distress, including a desire to travel to Las Vegas and lamenting missing New Year’s celebrations.
On December 15, 2020, deputies from the San Diego County Sheriff’s Rural Enforcement Division responded to a missing person report at the 14000 block of Great Southern Overland Stage Route. Although Nellom reported Mattingly missing on December 12, a fellow church member may have seen her walking north in Shelter Valley on December 13. Investigators learned that Mattingly was seeking a ride to Ramona or El Cajon. The Sheriff’s Department stated there was no indication of foul play but classified her as “missing at risk” due to unspecified health concerns. Despite this designation, the department did not confirm her dementia diagnosis and did not issue widespread public alerts.
Friends and neighbors expressed frustration over the perceived lack of urgency from law enforcement. Pastor Brian Kellar of Butterfield Community Church criticized the Sheriff's Department for limited investigative efforts, noting that deputies primarily took photos of Mattingly’s trailer rather than organizing a broader search. Nellom mentioned that Mattingly had lost a bank card with cash the day before she vanished and was visibly upset. She also noted that Mattingly had two estranged daughters and a granddaughter on Facebook, and was anticipating retirement benefits from her previous job with an auto company.
The case remains open and listed in the National Missing and Unidentified Persons System under case number MP145611. As of the latest update, there have been no confirmed sightings or developments in locating Diana Mattingly.Last Seen: Dec 12, 2020
