Mafia 1 was made by Illusion Softworks, directed by Dan Vávra. Same team then went to make Mafia 2. Unfortunately it took 8 years because their chosen engine for M2 (Renderware) was bought by EA and made unavailable for licensing. So after spending couple years with it they had to make a new engine and for next-gen (at the time) as well.
Dan Vávra wrote and designed lot of Mafia 2, but year before it was finished he left Illusion (now it was called 2K Czech because Take2 bought it and renamed it). He left because foreign management was meddling with the design and he got fed up, plus he spent couple years on projects that were not greenlit (incl. his version of Mafia 3 and HiTech, of which
video can be seen on youtube).
After he left, he spent few years finding investor for Warhorse so he could make Kingdom Come Deliverance. 2K closed Prague office in 2012 or so, so many people from there who worked on Mafia then went to Warhorse.
2K then established Hangar 13 in Novato, and added Brighton as well as integrating the remains of 2K Czech into it. So now Hangar 13 has 4 studios (Brighton, Novato, reopened Prague and Brno). They worked on the Mafia 3 as it exists and on Mafia 1 remake.