Complex sentence: Whelan attempted to reload his pistol, when Sergeant Corcoran, Officers Hafner, Deyer, Stengel and Kavainugh were able to hold him down and arrest him after a violent struggle.
Split into simpler sentences: Whelan attempted to reload his pistol, when Sergeant Corcoran. Officer Hafner, Deyer, Stengel and Kavainugh were able to hold him down and arrest him not without a violent struggle.