Schmahl as lead investigator in the defense of Alger Hiss on federal perjury and espionage charges by the United States from Wikipedia:

Re: Legal theory of who had burden of production, conflicts of interest, access to information, opportunity to falsify or place in false light.

Schmahl had worked for either the OSS or army intelligence during the war, then joined the Central Intelligence Group, which operated between the closedown of the OSS and the inception of the CIA. After his stint for the Hiss side, Schmahl defected to the prosecution team.