Gohumberry Tresp can be found dead in the premise resembling a bathhouse adjacent to the Basilisk Gate Barracks.
Gohumberry was killed by Orin the Red. His body was used as a component of Orin's "art" as an effigy to Balthazar, a monk Bhaalspawn defeated more than a century ago. He is decapitated, and his body is clad in monk-like robes.
Gohumberry Tresp's in-game model, as well as the model of Quelat Quimms (another dead human depicting Balthazar in the Undercity Ruins), is designed to copy Balthazar's image from the previous Baldur's Gate games.