Four people, including the general manager of the DNA event management company, have been held over Metallica Fan riot. The four members were arrested early today after fans rioted at the venue in Gurgaon for postponing the event at the last moment.Police said, they have been arrested on charges of cheating people and breach of trust.It may be noted that over 25,000 people had gathered at the lesiure valley park in Gurgaon to watch the concert.