The police on Saturday arrested a man for reportedly masturbating on a bus while staring at two women, who recorded the incident and posted it on social media.

"The perverted man, a hawker by profession, was arrested from Shyampukur police station area in the city," the Kolkata police said on its Facebook page.

The post of the city police, that also carried the photograph of the accused, said the man was arrested within hours of the matter being posted by the victims.

The police launched an investigation after one of the two women posted two videos on her Facebook page and also on the page of the Kolkata Police.

Two video grabs showed an elderly man making vulgar gestures and reportedly masturbating inside a bus. The victim on her Facebook post revealed that 15 days ago she and her friend had to go through a similar ordeal when the same man had dropped his pants and shown his genitals to them.

"When we protested and asked the bus conductor to take action, he ignored our pleas. Fifteen days back when the person had made vulgar gestures, we could not do anything as we did not have any proof. Today we have these two videos as proof and we want justice," the victim said in her Facebook post.

"We don't need any written complaint. The videos posted on our Facebook page is enough for us. We have already lodged a case," the Kolkata police said.