History of Forensic Nightmare

Overview

Forensic Nightmare is a Legendary Stasis Submachine Gun with a Precision frame at 600 RPM, introduced in The Witch Queen. Column 1 can roll Grave Robber, Perpetual Motion or Slideways; column 2 can roll Sympathetic Arsenal, Headstone, Kill Clip or Harmony.

Acquisition

It drops from Legendary engrams in Savathûn's Throne World after you complete the quest "The Gift of Appreciation" from Fynch, per Destinypedia. The game data lists a "Chief Investigator" triumph as its source, which Destinypedia does not mention. It is craftable with three patterns.