The city has tons of tall buildings so I think it sets this idea up nicely. The killer would essentially push the victim from the top of a building, and splat somewhere.
Impact would be cause of death.
Boot marks and fingerprints could be found on the ledge of the building that the victim fell from. You go to the victim’s house and there are suicide notes with fingerprints that don’t match the victim’s fingerprints. Witness reports moments before the event. Just throwing out some ideas for possible clues.