It is not sure who built this organ, as the sources contradict each other.
After GAUSE (1996: Tl.II, 111), the organ was completed in 1724 by Johann Josua Mosengel and it was still extant by 1944 (GAUSE ibid.). However, the facade does not resemble any of the beautiful facades of organs known to have been built by Mosengel (Königsberger Dom, Heiligelinde or Stockheim, Ordenskirche). FRITSCH (1930: S. 19) even renounces the facade as a "die in der Form künstlerisch wertlose Orgel" (i.e. facade without any artistic value).
After REICHLING & JANCA (2000: 370) the organ was built by Georg Sigismund Caspari and completed in 1726. Indeed, this instrument more resembles the organ of the Schloßkirche in Königsberg than it resembles any Mosengel instrument.
With Caspari being the son-in-law of Mosengel, it is easy to imagine that this instrument was erroneously attributed to Mosengel.
The photo below is from FRITSCH (1926: S. 20).
Mr. H. Müller (Siegen) kindly provided me with a copy of a larger photo of the organ. The facade is differently coloured than on the photo above.
The church was destroyed by the heavy bombings on Königsberg in 1944 and afterwards demolished.