An oil tanker sank in Johor waters after an explosion on board and six of its Indonesian crew members are missing. The Malaysian Maritime Enforcement Agency (MMEA) said it received information on the incident from the Singapore Police Coast Guard (SPCG) at about 5am on Thursday (June 15) that the MT Putri Sea could not be contacted by the tanker's agent. It said the incident could have happened 4.6 nautical miles south-west of Tanjung Pengelih in Johor. MMEA deputy director-general (logistics) Maritime Rear Admiral Datuk Mohd Taha Ibrahim said the agency sent a patrol vessel from Tanjung Sedili to investigate. He added that the Penggalang 15 reached the area at 6.15am and found the tanker not in sight, but there were traces of an oil spill in the area. A search and rescue operation involving four boats was activated at 12.30pm Thursday, Admiral Mohd Taha said. The missing crew members have been identified as Akhmad Faharuddin, 35, Muhamad Heri Hernanda, 28, Raden Abdur Rahem, 31, Rendy Alamanda, 28, Sulkifli, 39, and Yohanis Sumari, 35. The tanker, registered in Equatorial Guinea, is believed to have been carrying crude oil.