Li says she and her friends found the video odd because they knew men who specifically wanted to date larger women.They later launched the app together in November just to see what might happen, and they say the app already has 10,000 users and counting.After his release he lived at an address in England for a short time before indicating his intention to return to Glasgow.
Details of two other missing offenders were not being released, police said.
The police said they were in touch with the Canadian authorities with regard to the matter.
There are currently more than 3,500 registered sex offenders living in the community in Scotland - more than 1,100 of these are in the Strathclyde area.
At a news conference, police said Surjit Singh had been convicted of sexually aggravated assault in April 2005.
He was given a two month prison sentence and placed on the sex offenders register.