Specifically, Ingram also alleges that Nelson was used to protect an FRU asset known as "Stakeknife" alleged to be Frederico "Freddie" Scappaticci of the IRA's Internal Security Unit (ISU). Scappaticci denied this claim. Scappaticci was "Kerbstone". This was done via the assassination of World War II-era internee Francisco Notarantonio. Freddie Scappaticci is said to have volunteered his services as a spy in the late 1970s and that he eventually become the "crown jewels" (the best) in the hierarchy of British Intelligence IRA assets.