Elder abuse is a difficult crime to detect and prosecute. Detective Fernandes (D) began her investigation of Boyce (P) at the instance of Tunis's granddaughter, who told the detective that she thought P might be stealing from her grandmother. The granddaughter had discovered that all the furniture had been removed from Tunis's home and that she had been placed in a nursing home. The granddaughter had visited her grandmother in the nursing home and found that she seemed confused at first but later recognized the granddaughter and her husband. Tunis told them she did not know why she was there, that P had badgered her into signing what she thought was a document that said merely that she would think about signing a power of attorney, and that she was ashamed of the situation she was in and had not wanted to complain to the granddaughter. The nursing home stated that Tunis had granted P (who had signed Tunis into the nursing home) both a general power of attorney and a health-care power of attorney. The lawyer who had prepared the powers of attorney expressed surprise that Tunis had a granddaughter--he had thought she had no living relatives. Tunis had been in a shocking condition when admitted to the home, with multiple bruises and lacerations, and that the jewelry Tunis had worn on her previous admission to the nursing home was gone. The staff suspected elder abuse and decided to institute proceedings to obtain a new power of attorney, in which the nursing home would be the power holder. Tunis told D that P had threatened, slapped, and shoved her, had plied her with liquor, and might have (subsequent investigation revealed that she had) deposited her social security checks, without her authorization, in a joint checking account in P's and her name; that P had taken Tunis's furniture, and other personal property without her authorization and Tunis did not know what she had done with it. D learned that Tunis's Cadillac was parked in P's driveway and that the car, formerly registered to Tunis's deceased husband, was now registered to P. D arrested P, without a warrant, for the theft of the Cadillac, a felony. Investigation brought to light that P had in all likelihood forged a bill of sale of the Cadillac to herself for $100. Nevertheless, she has not been prosecuted. P sued D claiming false arrest and the court dismissed on grounds of immunity. P appealed.