A lawyer who also provided investment services has been struck off the rolls for misleading an investor into believing that the $250,000 he invested would be supervised by his law firm.

In disbarring Mr Malcolm Tan on Monday, the Court of Three Judges said the client, Mr Kuek Yak Yeon, had come to such a belief as a result of false statements by the lawyer.

The court also found that Mr Tan had made Mr Kuek sign two letters, purportedly to engage the services of his law firm, Keystone Law Corp, to fortify this belief.

"This is a case where the dishonesty violates the trust and confidence inherent in the solicitor-client relationship," said Chief Justice Sundaresh Menon, who delivered the decision.

The court, which has the power to suspend or disbar lawyers, said it intends to refer the matter to the Attorney-General to investigate "whether there are any criminal consequences".

Mr Tan, who also owns a business management consultancy called Bluesky Group, met Mr Kuek in March 2017 and promoted various investment products to him.

On Aug 28, 2017, Mr Kuek signed two letters of engagement under Keystone's letterhead and issued a cheque for $250,000 to Bluesky.

The letters stated that Mr Kuek would deposit his investment money with Keystone and Mr Tan would oversee the investments.

Mr Kuek said $150,000 was for a "guaranteed-returns investment", which promised 12 per cent per annum, and the other $100,000 for a "full-sum non-guaranteed investment".

In November 2017, Mr Kuek's representative wrote to Keystone for an update on the money.

Mr Kuek filed a complaint with the Law Society on Dec 12, 2017, after the law firm replied that it had not received any funds from him or carried out any legal work for him.

The Law Society laid seven charges against Mr Tan for, among other things, making fraudulent representations to Mr Kuek and placing himself in a position of conflict of interest by making the client pay the sum to Bluesky.

Mr Tan denied the charges. He argued that Mr Kuek was aware of his interest in Bluesky and that there was no conflict, as he was not providing legal services to Mr Kuek.

Before the disciplinary hearing in June last year, Mr Tan paid $125,000 to Mr Kuek, who then said he did not wish to pursue his complaint.

However, Mr Kuek was subpoenaed by the Law Society to testify.

The disciplinary tribunal found Mr Tan guilty on five charges and cleared him of two charges - of improper management of client money and for failure to account to Mr Kuek the investment sum.

On Monday, the court cleared Mr Tan of another two charges of failing to carry out his responsibilities as a lawyer.

The court noted that the core complaint is that Mr Tan never intended to carry out the engagement and that it was inconsistent to also charge him with not having carried out the engagement.