Between Deadeye and Angelo you have worked out the EXACT time of DEATH. Jacob may cast his spell with precision. The party also notices drag marks leading to the dumpster from one end of the alley. Which means Donnie was killed elsewhere and the body dumped in their dumpster. The marks lead out to the street. You see a homeless guy on the corner begging for change. Maybe he saw something. Also the store across the street has a security camera pointing towards the alley that could hold evidence.