Tan Boon An, 19, had allegedly pointed a knife at the girl and asked her to take off her t-shirt on the 13th floor lift lobby of a block in Choa Chu Kang Street 62.

He had already been charged earlier this month for another count of outrage of modesty.

In that incident, which took place inside a lift at block in Choa Chu Kang Crescent on Oct 6, Tan allegedly grabbed an eight-year-old girl by her shoulder, pulled her close to him and covered her mouth with his hands.

He has been remanded at the Institute of Mental Health for an assessment.