He posed as a young girl on a social networking site and was shocked by the number of men who wanted to have sex with "her".
It did not matter that he claimed to be only 14 years old.
When they sent their pictures over, he put them on his Facebook page to expose them. There are pictures of nine men he claimed tried to have sex with the "girl".
Mr Fai Marwan, 32, a bachelor, works in the hospitality industry. He is on a mission to rid the Internet of "perverts and paedophiles".
Lawyers told The New Paper that while it is entrapment, Mr Fai is not breaking any laws. But neither are the men he exposed.
But he is determined to push on. He said: "For me, this is a form of community service and I will continue to do it."
He does not even hide his own identity on his Facebook page.
He told TNP: "I have nothing to hide because I am doing the right thing.
"I have my own reasons why I never went to the authorities with what I have uncovered.
"I am not doing this to shame people, I am doing this to create awareness so that parents and people are aware of what's going on online."
Mr Fai said it was a conversation with a friend two weeks ago which got him started. Till then, he was sure Singaporean men would not prey on girls under the age of 16.
After all, the law is clear - girls of that age are protected because of their lack of maturity.
And those who prey on them can be jailed for up to 10 years.
"But my friend said that's not the case," Mr Fai said.
"She said there are men out there who are eager to hook up with girls as young as 14 if given the opportunity, and many of them turned to the Internet for such kicks."
Mr Fai's friend, who wanted to be known only Ms Iyah, confirmed the conversation.
The medical equipment sales representative, who is in her 30s, told TNP: "We were watching a video on Youtube and the show focused on sexual predators targeting young girls in America.
"Fai was certain such things didn't happen here.
"But I challenged him to find these men because if he looked hard enough, he would find such men even in Singapore," she added.
Curious and determined to do the right thing, Mr Fai accepted Ms Iyah's challenge.
And the results were disturbing.
Setting the trap
Two weeks ago, Mr Fai Marwan called himself "fgirl14" and prowled social networking website Alamak Chat.
Over the course of a few days, he said he was approached by nine different men, all in their 20s.
At first, the men asked Mr Fai for his e-mail address on the pretext of adding him as a friend on Skype.
He claimed these men became bolder on Skype and made lewd proposals during a chat.
Mr Fai, who called TNP hotline to share his experience, claimed: "During our chats, I asked these men what they wanted and the answer was always the same - sex."
"It didn't even matter to them when I said I was 14.
"One even said he always wanted to have sex with a 14-year-old girl. That, to me, is wrong."
Mr Fai said he tried to steer the topic away from sex during the Skype chats, which normally lasted less than an hour.
But the men, he said, were persistent.
Disgusted by these online predators, Mr Fai published screen grabs from his alleged chats with them on his Facebook page on April 14.
The posts, which are available only to Mr Fai's 1,963 friends, allegedly showed many chat logs between himself and the men.
The men allegedly asked for sexual acts shortly after chatting with him on Skype.
Some of the screen grabs even revealed names and pictures of the men involved.
In the private Facebook post, which he shared with his friends, Mr Fai displayed 81 pictures compiled from his "sting operation".
The collection included suggestive pictures as well as the men's profile pictures and contact details.
"After they sent me those pictures, they would ask for a web chat. But instead of seeing a girl, they would see me," he said.
"When they saw my face, they disconnected the chat and blocked me from their Skype friends list. I suppose they are embarrassed."
The post went viral and was re-posted on news commentary site The Real Singapore.
Mr Fai was quoted as saying on the website: "It is an embarrassing and a very disgusting act trying to have sexual intercourse with a minor.
"I will not stop publishing (pictures of) new predators. I hope with this method, we all can help spread awareness and prevent a certain crime from even happening (sic)".
While he said that no one has threatened him because of his posts, one of the men he encountered was his own friend on Facebook.
"He had the same nickname on Skype as he did on Facebook, so I tagged him when I made my April 14 post," he said.
But the man later sent him a message to say his Facebook account "was hacked".
He also removed himself from Mr Fai's friends list.
Did the men break the law?
Did the men commit a crime when they asked for sex from Mr Fai Marwan, who was posing as a 14-year-old girl?
Although sexual grooming is a crime, The New Paper spoke to five lawyers who said that the law also states that the offender must have communicated or met the minor on two or more previous occasions.
Veteran lawyer Chia Boon Teck said "there is no law" compelling Mr Fai to make a police report against those men, but he also believes the men cannot be charged for the acts "if they were merely discussed but not committed".
Criminal lawyer Amolat Singh agreed, adding that the men must also have "intentionally met or travelled with the intention of meeting".
The law is tough on predators who try to sexually groom children over social networks and is designed to catch anyone aged 21 or older who trawls the Internet with the intention of having sex with a minor.
The offence carries a maximum three-year jail term and a fine.
Did he break the law?
Did Mr Fai Marwan "entrap" the men by posing as a 14-year-old girl online?
Lawyers The New Paper spoke to certainly think so.
But lawyer Chia Boon Teck said this does not mean the men involved can claim they were set up when called up by the authorities.
This is because Singapore's laws are not sympathetic to entrapment as a defence.
Mr Chia explained: "A crime is a crime regardless of the circumstances surrounding the commission of the crime. At most, the men could mention the entrapment as a mitigating factor."
Agreeing, criminal lawyer Josephus Tan said he was uncertain if the authorities would take action even if the case was reported.
Doing so, he added, "will only open the floodgates" and serve to encourage more "cyber vigilantes" to take action over perceived wrongdoings online.
Did he do the right thing?
But the question remains - was this the right way to deal with the problem?
When asked, Mr Fai Marwan paused and replied: "What else can I do because reminding them that it is an offence won't help. They will still continue to do it."
Extreme measures are needed to deal with a problem like preying on underage girls, he said.
And by outing these men, Mr Fai said he was ultimately "creating awareness" of this persistent problem.
"My friends have been very supportive about what I've done. I also have a niece who is 14 years old. So what I learnt on (chat website) Alamak disturbed me greatly."
He also defended his actions - he may have posed as a teenager to draw out these men, but he denies ever "setting them up".
"They might say I was setting them up, but anyone in the right frame of mind would know that grooming a 14-year-old for sex is not the right thing to do," said Mr Fai.
"When someone says she's 14, why continue the conversation? What they should have done is to stop it and not gone any further."
This article was published on April 29 in The New Paper.Get The New Paper for more stories.