A video circulated online two weeks ago shows a man allegedly molesting a young woman on a train here. While the victim tries to slide away from the man, she remains seated next to him.

The man has since been arrested and charged.

Many netizens expressed disgust at his actions, but some wondered why the woman did not move away or even confront him.

Evelyn (not her real name) said people should not judge a victim's response to a molestation attempt.

The 29-year-old said she has been molested three times in public places. "I am relatively educated and outspoken, but I summoned up the courage to confront the man only when I was molested a third time, as an adult. What more a teenage girl?" said the civil servant.

"As a victim, you are caught off-guard. It can make you freeze, stay silent or act normal and pretend that it isn't really happening."

The first molestation incident happened on a bus when Evelyn was 11 years old. A man sitting beside her touched her chest and legs. She reported it to the police only many years later.

Then, as a university student, she was molested again while overseas on vacation. Once again, she froze.

But she gathered the courage to do something the third time she was molested, five years ago.

It happened on a train and though she walked away, something clicked and she decided to confront the culprit. By then, the man had left the train. While speaking to other commuters about the incident, a girl in school uniform said: "He touched me too." Evelyn took her to the control station to report the matter.

Ms Anisha Joseph, manager of the Sexual Assault Care Centre, the only specialised centre here that supports sexual assault victims, said it should be recognised that victims may find it difficult to stand up to the perpetrators. "While some victims may fight or take flight, freezing or being confused during the act is not at all unusual. There is no wrong way for a victim to behave or respond," she added.

The centre, which is run by the Association of Women for Action and Research, handled close to 100 molestation cases last year.

Sexual assault may be traumatic for some people and leave long-term psychological effects, such as depression or anxiety. Even witnesses may not know how to react.

Ms Winna Chin, who filmed the July 2 incident on the train travelling from Tuas Link station to Pasir Ris station, said in a Facebook post that she did not confront the man as she was afraid he would turn violent. "I did ask the girl to stand up but she chose to only move closer to her friend and not move away."

After the video and the man's photos were uploaded on Facebook, the police established his identity and arrested him at Hougang Mall.

Sim Teck Chye, 44, was charged in court on July 7.

Last year, there were 130 reports of outrage of modesty on public transport, according to provisional figures released by the police.

Molestation cases on buses and trains accounted for one in 10 of the total number of such cases reported last year. In 2011, there were 114 such cases. The number shot up to 163 in 2015, before dipping last year.

This month alone, at least two men were arrested for molesting women on trains. Besides Sim, police said a 33-year-old man was arrested when he alighted at Raffles Place station after allegedly molesting a woman on a train on July 10.

A spokesman for the Singapore Police Force said a molestation victim should shout for help immediately and call 999 to increase the chances of apprehending the suspect early. "Remember the prominent features of the suspect as well as his or her direction and mode of escape. If it is safe to do so, the victim or other witnesses of the crime may assist to detain the suspect while waiting for the police to arrive," said the spokesman.

While Ms Chin's photos and videos likely played a vital role in identifying the suspect, Ms Joseph said the photos or videos can make victims feel isolated and helpless, and subject them to further public scrutiny without their consent.

Molestation victims also include men and they may feel helpless too.

Bryan (not his real name), 29, said he has been molested six times by older men in toilets, buses, trains and taxis over the years, and froze each time. "I have been feeling very useless, cheap and paranoid through the years because of it," he said.

Ms Joseph said it is important to offer support, such as reassuring victims that it is not their fault and that whether or not they make a report is their choice. "We can also do more to make police and court processes less lengthy and daunting."

Yanny (not her real name), 25, for instance, is still waiting for the outcome of her case in April. She said: "The longer I have to wait, the more I dwell on it as there is no closure."

••Sexual Assault Care Centre helpline support is available on 6779-0282.