Cheryl was smoking outside her office in Chinatown, Singapore, when a man stood next to her.

At first, she thought he was fanning his shirt because of the heat. Seconds later, she realized that he was actually masturbating beside her. She yelled at him, managed to photograph him, and he walked away calmly, as if nothing had happened.

She wasn’t satisfied with that. Hours later, near the end of her shift, she saw him again crossing a bridge toward the Hong Lim Market and Food Centre. She alerted a colleague, chased him, and grabbed him by the neck until the police arrived. The 59-year-old man apologized, saying that he was drunk. She didn’t believe a word he said, and Singapore authorities confirmed his arrest that same Saturday afternoon on Upper Cross Street.

