The Tokyo Metropolitan Police Department has sent a team of investigators to the Philippines to bring back two of the four Japanese detained in an immigration facility. They have been on trial there in a separate case from what Tokyo police are investigating.

A team of about 15 investigators and officials from the Tokyo Police and the National Police Agency left Narita Airport near Tokyo Monday afternoon.

Tokyo Police have obtained arrest warrants for Watanabe Yuki, Kojima Tomonobu, Fujita Toshiya and Imamura Kiyoto on suspicion that they conducted telephone scams in Japan from the Philippines. Police suspect Watanabe is the leader of the group.

The two governments have been in talks on extraditing the four suspects, as Japanese police suspect they were also orchestrating a series of robberies in Japan.

Watanabe and Kojima cannot yet be handed over to Japan because their trials are still under way.

The team will take Fujita and Imamura back to Japan on Tuesday.

Tokyo police are set to arrest and question all the suspects as soon as they have been extradited about their possible links to the robberies.