FOR Mr Tan Boon Sin, Wednesday seemed to have started like any other.
The 67-year-old had gone for lunch with a regular client of Soc Leon Motor Works, his car workshop at Autobay@Kaki Bukit.
This was not unusual.
But when the pair returned to the workshop after lunch, Mr Tan left abruptly at 1pm without his client, whose car was still being serviced.
He told his staff that "he had to go", said the 55-year-old head mechanic of the workshop, who gave his name as Ah Siong.
He said he did not think anything was amiss, because there was no urgency in Mr Tan's voice.
But that would be the last time the mechanic saw his boss alive.
Mr Tan was found murdered at his Hillside Drive terrace home on Wednesday. His son, Mr Tan Chee Heong, 42, was also killed. The younger man was dragged by a car from the house to Kovan MRT station.
After leaving the workshop, Mr Tan reportedly made his way to the Certis Cisco Centre at Paya Lebar.
Chinese daily Lianhe Wanbao yesterday quoted a source as saying that he had withdrawn "bags of items" - including important documents and valuables - from a safe deposit box there.
A source told The Straits Times that police vans were seen parked outside the Certis Cisco building on Thursday afternoon, and that police had entered the building where the safe deposit boxes are located. It is believed that they were there to watch closed-circuit TV camera footage.
Sources also told The Straits Times on Thursday that the crime was linked to a business dispute.
Long-time customers of Soc Leon said the elder Mr Tan, who struck out on his own some 30 years ago, had been winding down his involvement in the business in recent years. Business had been good, said those who knew him.
But the younger Mr Tan did not appear interested in the business and was rarely seen at the workshop, said those who worked there. He was a director and shareholder at Aspern Singapore, an electronics products company.
A sales executive at Aspern, who gave her name as Vivian, said that as far as she knew, the company was not in any financial trouble. Nor was it seeking financing or involved in any mergers or acquisitions.
This was confirmed by the firm which does Aspern's bookkeeping, which said that its business was "healthy" and "financially quite strong".
The sales executive said she was on sick leave on Wednesday, and it was business as usual the next day when she went to work. The staff found out about their director's death only when reporters visited their premises.
She added: "Nobody knew that Mr Tan had died, no one mentioned that he was missing or uncontactable."
Additional reporting by Jalelah Abu Baker and David Ee