1. The scandal was revealed after months of undercover work by journalists.

2. But the covert groupings have had their undercover work rumbled by loyalists.

3. You have people who do undercover work, I believe, like mingle with students or go to political meetings.

4. On the other hand, Richard Walsh lacked Jack Bauer's outlaw tattoos - a few gained in undercover work; most part of Jack's personal roadmap.

5. Since 1997 an average of 20 investigations each year had involved undercover work.