Two officers died in the 2007 incident - the first fatalities in the line of duty in decades.

At the end of a 1 1/2 day inquiry on Thursday on the deaths of Senior Station Inspector Mohd Khalid Muhamad, 41, and Senior Staff Sergeant Heah Khim Han, 29, State Coroner Victor Yeo said he would deliver his verdict next Friday.

Crew of the two patrol boats gave evidence that they were in pursuit of a speedboat that had intruded into Singapore waters and ignored orders to stop.

Senior Staff-Sergeant Sharul Fairouk Khamis, who was steering the coast guard boat PK 50, said the speedboat, which he referred to as the target boat, was also making sharp dangerous turns and estimated the speed of the chase to be in excess of 45 knots or more than 80kmh.

Crew commander Mohd Khalid, told him to clip the target boat. He explained that clipping a boat meant using the hardened hull of the patrol boat to sideswipe the engine of the boat in front so as to immobilise it.

'As I was positioning my hull to clip the target boat, the crew commander shouted at me that PT 40 was nearby,' he said.

Two loud bangs later and he found himself underwater.

'It was very dark, my life vest was suffocating me and I was not sure whether I was facing up or down,' he said of the harrowing minutes.

He swam towards a light and broke surface. There was no sign of the crew commander and SSSgt Heah. Their bodies were recovered after an overnight search and rescue operation.

Earlier during the inquiry, senior investigating officer Christopher Jacob, told the coroner that PK 40 and PK 50 were both trying to clip the target boat. It was PK 40 that succeeded first and it sent the speedboat swerving right into the path of PT 50.