Complex sentence: He concludes in his 1993 history of the army that the allegations of torture were largely products of the British propaganda campaign, because the stories of widespread torture were not substantiated in the charges against the defendants in the Red Fort trials.
Split into simpler sentences: He concludes in his 1993 history of the army that the allegations of torture were largely products of the British propaganda campaign. Although isolated cases of torture may have occured, stories of widespread torture were not substantiated in the charges against the defendants in the Red Fort trials.