Seattle-based PopCap Games said today that it has debuted a new Facebook game, called Hidden Agenda, into beta. The new game is a hidden object game revolving around a murder mystery. The firm said that it plans a mainstream launch of the title next month, but the open beta will allow users to work with and against friends in solving the murder mystery. The company plans to released new "cases" in the game every month. PopCap is now part of Electronic Arts.