Chinese facial recognition technology developer SenseTime Group Ltd said it has raised $620 million in a second round of funding in just two months, adding that it continued to be the world's most valuable unicorn in artificial intelligence. The financing, which values the company at more than $4.5 billion, was led by Fidelity International, Hopu Capital, Silver Lake and Tiger Global and follows a $600 million funding round in April led by Alibaba Group. SenseTime, which became profitable in 2017, said in a statement it would invest further in research and development, and in securing talented researchers after the latest round of funding. SenseTime, based in both Hong Kong and Beijing, develops technology that employs AI to quickly identify and analyze identities using cameras, and has been used by Chinese authorities to track and capture suspects in public spaces such as airports and festivals.