supergrass

/ ˈsuːpəˌɡrɑːs /

noun

1. an informer whose information implicates a large number of people in terrorist activities or other major crimes

Example Sentences

The new names were handed over by a suspect turned "supergrass".

From The Daily Beast

All this is small beer compared with the supergrass that BCL Burton Copeland may turn out to be.

From The Daily Beast