It sounds more like an undercover grant of immunity plus pay or else!  National Security era.  I thought first of the ethical considerations of breaching client confidentiality and so forth.  “It was a different time back then son.”

“Senator McCarthy?”.

“It was a different time…what was it you said, national security.”

The Hiss Trial

• Richard M. Nixon
• Roy Cohn
• “Double- Agent”-like investigator [he knew too much]

Investigators name is attached to case.  At first he worked as an investigator in the Hiss’ interest, then he worked for the prosecution in securing a guilty verdict.  Recent evidence disclosed reveals facts making it more probable Hiss was guilty as charged by the Nixon Administration.

https://johnrubens.wordpress.com/2016/05/12/a-light-clicked-on-regarding-the-investigator-for-the-hisses-alger-hiss-flipped-to-help-prosecution