Team Bondi, the Team behind, L.A Noire, was closed time ago. They were working on Whore of the Orient an unreleased and unannounced game before the closure. Warner Music uploaded a song for a second iteration of L.A Noire to YouTube. The song was removed, but not the evidence of it:
I highly doubt that a second part of L.A Noire is in works, but at least we know that the sequel was in development for a specific time.