Police said a three-officer tactical unit was on patrol at 70th Street and Throop Street around 2:40 p.m. Monday when, according to police, 20-year-old Janice Lewis called them murderers and shouted profanity at them. According to police accounts, when officers stopped, Lewis spit on one of them, and the officers got out of their car to take her into custody. Then police said someone, later identified by authorities as 19-year-old Senneca Traylor, threw a 2x4 that struck one of the officers in the back of the head. Police said Traylor fled into a nearby residence, and they followed him inside to take him into custody. Once inside, officers said there was a struggle with Traylor and a man identified by police as 28-year-old Robert Williams.