tripoli libyan force act anti-crime unit tripoli say arrest organisers comic festival act indecency public morals arrest carry special deterrence force rada salafist-led arm group expand power libya u.n.-backed government national accord salafists ultra-conservatives whose influence grow across libya recent years arrest cut short second three-day annual comic con festival arts comics anime game hold capital arrest make friday second day event libyans attack comic con organisers social media hold event say un-islamic resemble halloween party organisers say facebook page festival nothing halloween post immediate comment arrest rada say statement festivals like comic con derive abroad exploit weakness religious faith fascination foreign culture organisers supervisors event arrest present public prosecution act indecency public morals say statement necessary address destructive phenomena fight drive dissemination pornography fee mind teenagers motivate kill mutilate well-known cartoon libyan salafist-led force break comic festival 'indecency