What is this aircraft from ca. 1925 (crash included)?
Looking at the holes in the engine cowling, landing gear, struts and wires configuration and general geometry, it may very likely be a 1918 Halberstadt C.V 


(source)


(source)

Horizontal stabilizer and elevator shape, handles on the upper wing, "square grid" on the upper wing, also tells it is a Halberstadt CV

This document explains how swiss military aircrafts/airships are numbered.

Aircrafts numbered 64 and 703 were supposed to be DFW C.V But the one in the pictures you provided is definitely a closer match to Halberstadt C.V, anyway there were also DFW C.V built by Halberstadt company. Most surprising is the fact that number 85 is missing.