The proactive investigation attempts to get the child molester to reveal his or her illegal activity and to identify current and past victims. Since many preferential child molesters produce and collect child pornography and often trade or sell portions of their collections with other molesters, the task of the investigator is to gain the child molester's trust and encourage the child molester to discuss his or her illegal activities. Child molesters often need validation for their activities, and they sometimes join underground organizations such as the North American Man Boy Love Association. Membership allows child molesters to meet each other and receive the organization's publications. Pedophiles often place personal adds in these publications, although only a few publications are still in circulation. Police officers can advertise in adult contact publications to identify child molesters and individuals involved in child pornography. The use of undercover advertisements can be effective, as demonstrated by a multiagency task force in San Diego that identified, arrested, and convicted more than 75 individuals through an undercover operation.