Paper money for the dead was strewn outside Lai Chi Kok Reception Center last Thursday. A paper man was placed at the center's entrance, with the name of the correctional officer written on it.

Following investigations, Sham Shui Po and West Kowloon police made the arrests over the weekend. Four of the arrested were inmates who had been remanded at Lai Chi Kok Reception Centre, waiting for their court appearance.

There was a conflict in the center back in September concerning gang interests. Two inmates were isolated and disciplined by correctional services after the conflict, and the elite unit “Black Panther” Regional Response Team was deployed to the center.

Police suspected that the four were unhappy about the arrangement and came up with a plot to retaliate against the officer involved.

They were believed to have given instructions to a woman who visited them in the end of October.

Police are still hunting down a masked man who took a taxi and carried the paper offerings to the scene. Those who witnessed the incident are urged to contact the police.