police leading him handcuffed to an ambulance. tomorrow he makes his first court appearance, facing ten counts of first degree murder. investigators are working to unravel a motive, scouring the crime scene for clues, trying to piece together why that location. and whether the gunman was targeting someone specific. alissa lived in this suburban house and according to family members in that police affidavit he had been acting strangely in the days leading up to the shooting. fiddling with this ar-style gun and they suggested he had suffered from some sort of mental health issue. he is a u.s. citizen who came here from syria as a 3-year-old. high school classmates reportedly described him as pleasant, but also quick to anger. they tell "the denver post" heo peers. sources tell abc news investigators have developed a picture of an angry man with a short fuse and very possibly underlying psychiatric problems. and they're trying to learn if he had any connection to