A Minneapolis police officer has been charged with sexually assaulting teen girls he met on social media sites, including one girl described as mentally or physically impaired. Thirty-two-year-old Bradley James Schnickel was charged Friday with three counts of attempted or actual third-degree sexual conduct and three counts of engaging in sexually explicit online chats with a minor. The charges carry a maximum prison sentence of 46 years. Anoka County prosecutors say Schnickel had online chats with four girls who were 13 or 14, in which he described wanting to engage in sexual activity. The criminal complaint says he had physical contact with some of them. Schnickel, a five-year veteran, is on administrative leave.