SANTA ANA, Calif. (KABC) -- An 80-year-old missionary and former pastor was charged with sexually assaulting two girls under the age of 10, according to the Orange County District Attorney's Office.Prosecutors said Douglas Whinery, of Tustin, approached a 10-year-old girl and her 8-year-old relative at a park in Tustin on Nov. 7, 2011.Whinery groomed his victims by befriending their family, providing money for a place to live, taking the victims to school, having the victims spend the night in his home, and inviting them to attend church with him, according to prosecutors.He was actively involved at Olive Crest Church in Santa Ana, Foothill Family Church in Foothill Ranch, and Grace Church in Yorba Linda, according to prosecutors.The district attorney's office originally stated Foothills Church was in Rancho Santa Margarita, but later clarified it was in Foothill Ranch.Officials stated Whinery sexually assaulted the two victims on multiple occasions between Nov. 7, 2011, and March 28, 2016.Prosecutors said the youngest victim reported the sexual assaults to a family member on March 28 and Tustin police were contacted.Whinery was arrested on March 30 and later charged with four felony counts of lewd acts upon a child under the age of 14, and two felony counts of oral copulation or sexual penetration with a child 10 years old or younger, with a sentencing enhancement allegation for committing lewd acts upon multiple victims.If convicted, prosecutors said Whinery faces a maximum sentence of 100 years to life in state prison.Police said their investigation was ongoing and urged anyone with additional information, or anyone who believed they may have been a victim of Whinery, to contact Supervising District Attorney Investigator Mark Gutierrez at (714) 347-8794.