Karl Ross was a dog groomer; Kitty Genovese's neighbor and "friend" who witnessed the second attack on her. His excuse for not immediately calling the police or assisting her was that he was a.) drunk; and b.) not certain that the woman being murdered was Kitty; and c.) he didn't want to get involved.
He did call or talk to friends and neighbors about what he ought to do. Finally he talked to Sophie Farrar, who told him to call the police and then immediately ran down to help Kitty. Some commentators, noting that Ross was a closeted gay man when homosexuality was illegal, thought that he was therefore afraid to contact the police.