Japanese police are sending investigators to the Philippines to bring back at least two of four fraud suspects to Japan. They are also suspected of links to robberies, including one case involving an alleged murder.

The Tokyo Metropolitan Police Department obtained arrest warrants for Watanabe Yuki, Kojima Tomonobu, Fujita Toshiya, and Imamura Kiyoto on suspicion of involvement in phone scams and requested Philippine authorities to extradite them.

Watanabe is alleged to be a ringleader of a fraud group based in the Philippines.

Investigative sources say the governments of the two countries are coordinating for the handover of at least two of the four Japanese nationals being held at an immigration facility near the capital, Manila. Fujita and Imamura are expected to be handed over on Tuesday.

Watanabe and Kojima cannot be extradited as they are facing trials on suspicion of committing violence against women.

If a Philippine court dismisses their cases in hearings on Monday, all four can be handed over to Japan as early as Tuesday.

The four men are also suspected of having issued instructions to the perpetrators of a series of robberies in Japan from the detention facility.

Tokyo police say about 15 officers, including some from the National Police Agency, will leave for the Philippines on Monday.

The police plan to arrest the suspects and interrogate them on suspicion of fraud and involvement in the robberies.