A team of police officers from the Criminal Investigation Department (CID) returned to the scene of July's Kovan double murder on Saturday and left with bags of evidence hours later.

They were seen gathering evidence at the 14J Hillside Drive corner terrace unit, where car workshop owner Tan Boon Sin, 66, and his son, businessman Tan Chee Heong, 42, were killed on July 10. The officers only left at about 7.15pm.

Three of the victims' family members, including Mr Tan Chee Heong's older brother and younger sister, were also at the home and left shortly after the officers did.

Senior staff sergeant Iskandar Rahmat, who has since been charged in court for the double murder, was not at the scene. The 34-year-old suspect has been remanded for psychiatric assessment. The case against him will be heard in court again on Aug 30.