A group of pranksters who pretended to be plainclothes officers in order to terrorise illegal cigarette peddlers may have got themselves in trouble with the real police.

The pranksters, who call themselves MerlionTV, uploaded a two-minute video on Jan 14 called "Scaring the s*** out of illegal dealers in Red Light District".

It shows a crew member approaching cigarette peddlers in Geylang and pretending to be an interested customer.

But right after, he walks away and pretends to speak into a mouthpiece. In one segment, he is heard saying: "10/20 Romeo, we found a subject, we found a subject."

Another crew member then lunges from the shadows, and the peddler is then seen running away desperately. The crew members give a short chase before returning to the abandoned cigarettes and showing off the goods.

Three peddlers, all seemingly foreigners, were targeted in the video, which carries a disclaimer saying the crew "did not impersonate any police officers or law enforcement entities".

That has not stopped the police from launching an investigation. The police told The Sunday Times that a report has been made against the video, which has attracted almost 57,000 views on YouTube.

It has also attracted plenty of mixed comments. Some found it "funny", while others thought the group had "gone too far".

This is not the first time the pranksters, who appear to be local, have attracted controversy.

Last October, just after the MerlionTV YouTube channel was set up, the group posted a video showing a masked man walking around Singapore with a knife and scaring unsuspecting people. This also set off a police investigation after complaints were made.

Since then, the group has posted three more videos, roughly once a month. In one of them, a masked man is seen waiting for a bystander to come along before smashing the head of a dummy with a sledgehammer. The head bursts in a splash of red liquid, and the person, frightened by what he has just seen, runs off.

The members of MerlionTV have kept their identities secret by agreeing to interviews only through e-mail. The group's social media editor, who called himself "Andrew Smith", told The Sunday Times that the police have not been in contact over the latest prank. He said: "The video that was uploaded recently is strictly meant for humour and entertainment purposes, as well as raising awareness of the vice operations that are ongoing for decades."

He added that the cigarettes were not kept by the group but handed to "relevant departments".

Criminal lawyer Josephus Tan said it was unlikely the group would be charged with impersonating public servants. "The threshold for impersonation is quite high, usually you need some form of hard evidence, like a forged ID, uniform or to say some words to cause a misrepresentation," he said.

But he added that the group could get in trouble for causing a public nuisance.

"Because of their actions, they might cause alarm. People might think there's a police chase going on - but the alarm created is not justified, it's a false alarm."

dansonc@sph.com.sg