Telegram was developed in the VK offices for a long time after VK was supposedly "stolen" from Durov.

>left the country with no interest in returning

Well, except for when he does

https://tjournal.ru/tech/52954-durov-back-in-ussr

http://uip.me/2016/04/dark-side-of-the-telegram/

https://lenta.ru/news/2017/03/20/durov/

https://medium.com/@anton.rozenberg/friendship-betrayal-clai...

https://theoutline.com/post/2348/what-isn-t-telegram-saying-...

https://twitter.com/ChristopherJM/status/910186197598838784