From April 1944, numerous test rockets were falling near Sarnaki village, in the vicinity of the Bug River, south of Siemiatycze. The number of parts collected by the Polish intelligence increased. They were then analyzed by the Polish scientists in Warsaw. According to some reports, around May 20, 1944, a relatively undamaged V-2 rocket fell on the swampy bank of the Bug near Sarnaki and local Poles managed to hide it before German arrival. Subsequently, the rocket was dismantled and smuggled across Poland. Operation Most III (Bridge III) secretly transported parts of the rocket out of Poland for analysis by British intelligence.