Prime Minister Lee Hsien Loong has thanked members of the public for their concern.

This was after three videos of his eldest son, Li Yipeng, were taken and put up online.

The videos were taken without Li's permission or knowledge.

PM Lee's statement

In response to media queries on March 17, Chang Li Lin, PM Lee's press secretary, said that the prime minister was aware of the incident, the videos and a fake Facebook post about the incident.

Chang said: "It is of concern that a vulnerable person can be taken advantage of like this."

"Yipeng happens to be PM's son, but many other vulnerable persons go about Singapore on their own, and they must be able to do so safely, without being taken advantage of or harassed and without their privacy being breached."

Li, who has Asperger's syndrome, is PM Lee's second of four children.

PM Lee also has a daughter and two other sons.

Would not comment further

Chang also said PM Lee would not comment further as the matter was being investigated by the police.

She added: "PM Lee thanks the members of public who have expressed concern about the matter."

What happened

A series of three videos began circulating on Saturday, March 16 on Facebook and chat apps.

They showed PM Lee's eldest son, Li Yipeng, being questioned at a taxi stand and in a car.

The camera recording was trained on the 36-year-old seated in the back seat.

The Singaporean driver is a 31-year-old male.

The vehicle Li got on was not a private-hire car.

In the videos, the man had offered and given Li a ride.

The driver was heard asking Li repeatedly to confirm his identity, his residential address, and the security and travel arrangements for him.

Li appeared uncomfortable and he told the driver that the line of questioning was inappropriate.

Police investigating

Two men are currently assisting the police in their investigations.

One man is the 31-year-old driver, while another 39-year-old man is assisting investigations into the photo showing a Facebook post supposedly made by PM Lee about the incident.

The post has been established to have been doctored.

The driver has had previous run-ins with the law.