A veteran Sacramento police detective has been arrested on charges of defrauding a mentally impaired 80-year-old woman of $100,000 after arresting two con artists for victimizing the same woman, police said. Burglary Detective Milton Casey, 38, was released on $10,000 bail after being booked on suspicion of grand theft and embezzlement. The arrest came less than three years after Casey, an 11-year veteran of the Sacramento Police Department, made two arrests in a case also involving Mary Clark, who is described by associates as forgetful and vulnerable. Casey has been placed on an administrative leave pending the outcome of the criminal case and an internal investigation, a police spokesman said. He is accused of talking Clark into selling more than $100,000 worth of blue-chip stocks and persuading her to transfer the money to him.