He molested a 14-year-old schoolgirl in a lift in 2012 but was never caught.
Four years later, Dexter Louis Wong, 35, molested another teenager in a Housing Board lift lobby near where he lived and was arrested a day later.
He then admitted to the offence committed in 2012.
Yesterday, Wong, an unemployed father of one, was sentenced to five years' jail and 10 strokes of the cane for molesting the two girls.
A second count of molesting the younger victim was taken into consideration.
Deputy Public Prosecutor Michael Quilindo said Wong had trailed the older 17-year-old victim to her lift lobby, in the eastern part of Singapore, on Sept 10 last year without her knowledge.
He got into the lift with her and got out when she did.
He then grabbed her neck from behind and molested her.
She screamed but could not get away.
Wong then fled, and the victim ran home and told her mother.
Knowing the police would be looking for him, Wong removed his shirt before he ran up the staircase to his flat nearby to escape detection from the closed-circuit television cameras in the area.
For the earlier case, the court heard that Wong was out jogging on Nov 14, 2012, when he saw the 14-year-old girl and decided to follow her into the lift at her block.
He molested her before he ran out of the lift on the 10th floor, but he came back when he realised that there was no staircase for him to make an escape.
As the lift went up, he molested the victim again.
Getting out on the 14th floor, she pressed the call button on the lift landing to prevent the door from closing, and Wong from fleeing.
But he got away by pushing her to the ground.
An Institute of Mental Health report on Wong stated that there was "considerable risk that (he) may reoffend. It is of concern that he chooses to target vulnerable subjects such as schoolgirls".
His lawyer, Mr Edmond Pereira, said the accused had committed the offences "out of despair and frustration" but added: "We agree that this is no excuse for his actions."
Wong could have been jailed for up to 10 years and caned on each charge.
This article was first published on Jan 13, 2017.
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