SINGAPORE - He was clearly unprepared for the stark change.
The retired senior police officer initially thought he was being shown a video clip taken in a neighbouring country.
It showed scores of prostitutes loitering in the streets while men haggled with pimps.
John, who asked not to be named, had asked this reporter at first: "Which country is this?"
When told that the clip was shot in Geylang last Wednesday night, his expression betrayed his shock and disbelief.
"It can't be," John said yesterday. "Are you sure this is Geylang?"
For ex-cops like John, who had patrolled and been involved in operations in the area in the 1990s, the streets of Geylang were never this "lawless".
"The only persons loitering the streets back then were pimps," said John, who was formerly attached to Central Police Station and had not ventured into Geylang since his retirement.
"They (illegal activities) were contained within a 70m stretch of back alley between Lorong 2 and Lorong 4 Geylang. I can assure you there were zero China girls walking the streets in the whole of Geylang."
Fast forward more than two decades, and Lorong 2 Geylang has been demolished to make way for Sims Way and the Kallang-Paya Lebar Expressway.
Yet the sleaze has not left Geylang. What made the area evolve? John did not have an answer.
"We sometimes faced manpower shortages in dealing with crime in Geylang," John said, "But how we worked around it was by using reservist police officers."
That strategy helped John and other senior commanders in dealing with robberies, illegal gambling, sale of sex drugs and illegal brothels.
As a result, lookouts working for the prostitution syndicates were unable to distinguish between reservist officers and familiar police faces.
Briefings held before raids were conducted away from the Central Police Station.
The plainclothes reservists sent to infiltrate the Geylang crowd were also told to take buses to the raid's location.
"This way, the criminals were not able to notice the police build-up until it was too late," John said.
"Our commanders had always emphasised that we take control of the situation before criminal activities spilled out of Geylang and into the heartlands."