A teenager was shot and killed by police in Brooklyn Monday night, witnesses said. Police say they received a 911 call after 7 p.m. about a mother-son dispute on Gates Avenue. Shortly after arriving at the home in Bedford-Stuyvesant, officers opened fire on the son. Witnesses said the 18-year-old victim had jumped out of the first-story window with a hairbrush in his hand and ran from police before officers opened fire. The teenager was taken to a hospital and was pronounced dead. His identity hasn't been released. Investigators remained at the shooting scene late into the night. They haven't said why police opened fire on the teenager. At least 14 bullet casings were circled on the ground as part of the crime scene. Information from The Associated Press was used in this report.