Singapore police on Thursday arrested seven more people in connection to the December 17 murder of a man at a Shell petrol station in Taman Pelangi.
"Seven of those detained, including three women, were arrested in Singapore on Wednesday with the help of the Singapore Police Force," Johor police chief Mohd Khalil Kader Mohds told The Star.
The Singapore Police Force (SPF) confirmed on Thursday night that the seven suspects are Malaysian and are aged between 19 and 23.
SPF added that all seven have been handed over to Malaysian police on Thursday to aid in investigations
Earlier reports said that a 22-year-old man and a 19-year-old woman were first arrested in Penang on December 20.
Later, it was reported that another four people had been detained during an operation in Johor on Thursday.
The Singapore arrests bring the total number of detained suspects to 13, all between the ages of 16 and 26.
The victim, Tan Aik Chai, died after he was stabbed in the heart and mowed down by a car with four men inside.
The 44-year-old, who is believed to be a leader of an underworld organisation, was using the air pump at the petrol station to inflate the tyres of his car when he was attacked.