In Manhunter 2, look at the side of the tram at Cable Car Barn to see posters of Manhunter: New York and Manhunter 3: London (which was never released).
Manhunter 3: London is a cancelled post-apocalyptic adventure game that was going to be designed by Barry Murry, Dave Murry, and Dee Dee Murry of Evryware and published by Sierra On-Line. It was to be the third game in the Manhunter series following Manhunter 2: San Francisco, taking place in London with the Manhunter tracking down Phil Cook and driving the Orbs away from Earth. It game would then be followed by Manhunter 4.