Police on Tuesday arrested three Vietnamese nationals and charged them with robbing compatriots.
The men are being held in an investigation into a gang of Vietnamese extortionists which was behind the March 20 body-in-a-bin murder in Bangkok's Bang Phlat district.
The three men arrested on Tuesday were identified as Tran Ta Huang,, 25, Ngo Duc Tang, 19, and Dang Huu Lanh, 18, Pol Col Thanawat Wattanakul, chief of Chok Chai police station said.
The suspects and two other 20 year-old Vietnamese males still at large were accused of using knives to rob 7,000 baht and two smart phones from Nguyen Van Vo, 19, and Nguyen Van Nam, 24, at a restaurant in Soi Sukhonthasawat in the Lat Phrao area on May 9.
The armed robbery was led by Mr Huang, who earlier had an argument with the two victims, police told the media.
Police apprehended him at Phahon Yothin Soi 87. Further questioning of Mr Huang led police to arrest the other two men in Taling Chan district.
The suspects allegedly admitted to their crime but said it was only their first one.
Police doubted this explanation. Inspections of their mobile phones indicated contacts between them and a Vietnamese gang extorting money protection fees from compatriots. The gang was also believed involved in the murder and dismembering of a leading member of a 32-year-old alleged criminal identified as Hoang Trong Hung, Pol Col Thanawat added.