OTTERBEIN, Ind. — A Silver Alert has been issued by Indiana State Police for a man missing from a city just outside of West Lafayette. The Otterbein Police Department is investigating the disappearance of 43-year-old Donald Whistler, described by police as a 5'2", 100-pound white man with brown hair and blue eyes. Whistler was reportedly last seen wearing a dark blue shirt and green khaki pants shorts. A photo of Whistler, provided by ISP, can be seen below: Donald Whistler (via ISP) Whistler reportedly went missing around 8 a.m. on Sunday, Oct. 20, and was last seen in Otterbein. He is believed to be in extreme danger and may need medical assistance. Anyone with information on Whistler's whereabouts is being asked to call OPD at (765) 884-0080 or 911 immediately. To remain anonymous, call Crime Stoppers of Central Indiana at (317) 262-TIPS.