SINGAPORE - When he joined the police force in April last year, Sergeant Desmond Heng, 25, never imagined he would one day wade in canal water to help arrest a suspect.

But he found himself doing so last Saturday (Sept 29) to help nab a suspect who allegedly harassed members of the nearby Church of Our Lady of Lourdes in Ophir Road.

The Straits Times understands that the man had approached some women in the church and made them uncomfortable with his actions.

One of the women was shocked by the encounter and ran out of the church building. The man followed shortly after.

The suspect later appeared to try to flee from the police in nearby Rochor Canal.

A snippet of the episode at Rochor Canal was captured on camera, where Sgt Heng is seen supporting the shirtless suspect in the shoulder-deep water while another officer rushes to grab a life buoy.

"The thing I was most worried about was that he would struggle in the water and give me difficulties," said Sgt Heng at a media briefing on the case on Tuesday (Oct 2).

Another challenge, he added, was communicating with the man as the suspect was in a drunken stupor and did not appear to understand English.

"My main focus was on locating him and quickly bringing him up, as he would sometimes be submerged in the water," said Sgt Heng, who added that the man also reeked of alcohol and was laughing hysterically.

The decision to rescue the man was made by Inspector Ishak Mohali after discussions with the team, and Sgt Heng was chosen to enter the canal as he is the most confident swimmer.

The decision to enter the canal was also taken to save the man's life, as he appeared drunk and there were concerns that he could drown.

When the first two police officers arrived at the scene after a call for assistance at about 1.30pm, the man was seen lying face-up in a 3m-deep drain in shallow water, with a cut on his chin. But he did not respond to the police, and instead got up and walked unsteadily in the direction of the canal that was linked to the drain.

He eventually reached a tunnel that led to the canal and swam into it.

The officers initially decided not to engage the man as the drain's slippery surface, covered with algae, meant the chances of slipping and getting injured were high.

Instead, a backup team of six was called to go to Rochor Canal directly, among whom was Sergeant Heng.

He entered the water using a ladder on the side of the canal, and kept his uniform on so he could be identified as a police officer. He also left his boots on for safety.

His colleague, Sgt Caleb Kok, 24, was also ready to enter the water should Sgt Heng encounter any difficulties. After about 10 minutes, they managed to haul the man up to land, where he was checked by paramedics.

The 26-year-old suspect was arrested for using abusive words against a public servant, intentional harassment and drunkenness in a public place. Investigations are ongoing.

Sgt Heng, who learnt swimming from his uncle, said it was the "most unique" experience he has had since he started patrolling in the Rochor area 11 months ago.

Asked about his reaction to the viral video, he joked: "(I feel) that I looked very ugly, my hair was just in a mess - a disaster."

He added that while the negative comments online have not affected him, his teammates have been teasing him about the video.

"A lot of media attention has been directed at me, I just hope to direct the attention to the police force... I did not act on my own and knew I had support," he said.