Complex sentence: Around 1995, an undercover detective discovered that there were 1,100 people on the rolls, and in 1997, NAMBLA was the largest group in Ipce, an international pro-pedophile activist organization.
Split into simpler sentences: Around 1995, an undercover detective discovered there were 1,100 people on the organization's rolls. In 1997, NAMBLA was the largest group in IPCE, an international pro-pedophile activist organization.