A hairdresser set up an account on online marketplace platform Carousell in 2016 and offered to pay female students who were willing to record upskirt videos of themselves while wearing their pinafores.
Ivan Seah Kim Ming, who called himself "upsktfan", offered the girls $35 for a two-minute video and $45 for a three-minute one.
Seah also provided the girls with a script and offered additional cash if they recited from it.
These included phrases such as "Hey what are you looking at? Do you like to see me adjust my shirt?" and "Do you like to look at my panties underneath?"
Three girls later approached Seah and sent him their videos, a court heard.
Besides these, he also recorded upskirt videos of at least 25 different victims at various places, including his home and MRT stations.
The 37-year-old Singaporean pleaded guilty yesterday to 11 counts of insulting a woman's modesty. He committed the offences between 2007 and 2017.
Another 17 charges, mostly for similar offences, will be considered during sentencing.
In one instance, some time between January 2007 and November 2016, he targeted a girl from a local junior college and used his mobile phone to record upskirt videos of her on an overhead bridge.
Seah also committed similar offences against his other victims at places such as Far East Plaza, as well as Bras Basah and Bishan MRT stations.
His offences came to light when a 34-year-old woman alerted the police on Aug 16, 2017, about his activities on Carousell.
Calling Seah a "pervert", she told officers: "He is offering young girls who want to earn more money to contact him and to take upskirt video of themselves. This is disturbing. Please do something about this."
Officers conducted an investigation and seized from Seah items including his mobile phone and an external hard disk.
Seah was later found to be in possession of 253 obscene films and at least 26 upskirt video files. He also had 955 films that did not have valid certificates.
The court heard yesterday that, according to Seah, he had heard voices in his head asking him to commit the offences.
District Judge Toh Han Li has called for a report to assess his suitability for a mandatory treatment order (MTO).
Offenders given an MTO have to undergo treatment for their mental condition in lieu of jail time. Seah will be sentenced on May 11.
For each count of insulting a woman's modesty, offenders can be jailed for up to a year and fined.
Correction note: This article has been edited for clarity.
