Nine persons have been booked following a complaint from a woman alleging harassment for participating in a flash mob here on the sidelines of the ongoing International Film Festival of Kerala. The case was registered based on a complaint of one Jasla Madasseri, a woman hailing from Manjeri in Malappuram district of north Kerala, police said. As per her complaint, she was harassed via various online platforms including WhatsApp groups and Facebook.She received several threat calls also, a police officer said. According to Jasla, they had abused her on social media platforms as well as through telephone for taking part in the event at Tagore Theatre here, the main venue of IFFK, on Sunday. Museum police here said the case was registered under various IPC sections and Information Technology Act. The flash mob, in which Jasla participated, was organised by a social media group to protest the recent online attack on three Muslim girls who took part in a similar event at Malappuram as part of an AIDS awareness programme.