A NATIONAL University of Singapore undergraduate who allegedly molested three teenage boys in Housing Board lifts near their homes appeared in court on Tuesday to face charges.

Andy Lee Kee Liang, 24, is also charged with performing oral sex on one of the boys, and forcing him to perform the same act on him.

Lee claimed trial to five charges - two each of aggravated molestation and unnatural sex and one of attempted outrage of modesty - committed in August and September 2007.

He elected to remain silent when Community Court Judge Roy Neighbour called for his defence, claiming he was of unsound mind at the time of the offences.

In a statement of agreed facts, Deputy Public Prosecutor Isaac Tan recounted Lee's acts.

The first victim was a 14-year-old boy, whom Lee followed from an MRT station to his block of flats on Aug 30 that year.

At the lift lobby, Lee exposed himself to the boy, then got into the lift with him.

He positioned himself in front of the victim, put his hands on his shoulders and kissed him on the lips. He also groped his private parts.

Filled with fear, the victim struggled and tried unsuccessfully to free himself.

Lee then knelt down and performed fellatio on the victim. He continued molesting him and stopped only when an elderly man entered on the eighth floor as the lift was going down.

Read the full story in Wednesday's edition of The Straits Times.