Does "the investigating US microbiologists" mean "the US microbiologists who investigated Ishii"?

In addition, should there be a comma before " that information will be retained in intelligence channels"?

Context:

Arrested by the US occupation authorities at the end of World War II, Ishii and other Unit 731 leaders were to be thoroughly interrogated by the Soviet authorities.[6] Instead Ishii and his team managed to negotiate and receive immunity in 1946 from war-crimes prosecution before the Tokyo tribunal in exchange for their full disclosure of germ warfare data based on human experimentation. Although the Soviet Russian authorities wished the prosecutions to take place, the USA objected after the reports of the investigating US microbiologists. Among these was Dr. Edwin Hill (Chief of Fort Detrick), whose report stated that the information was "absolutely invaluable", it "could never have been obtained in the USA because of scruples attached to experiments on humans", and "the information was obtained fairly cheaply".[6] On 6 May 1947, Douglas MacArthur wrote to Washington that "additional data, possibly some statements from Ishii probably can be obtained by informing Japanese involved that information will be retained in intelligence channels and will not be employed as 'War Crimes' evidence."[7] The deal was concluded in 1948.[citation needed] In this way Ishii was never prosecuted for any war crimes.

More:
http://en.wikipedia.org/wiki/Shir%C5%8D_Ishii#Immunity