Theresa Villiers grab re: IRA letters

The transcript discusses individuals connected to terrorist offences and clarifies that having a letter does not protect them from prosecution. These letters only indicated that, based on known facts at the time, they were not sought for arrest. If new evidence arises, they would face normal criminal procedures. The letters do not provide immunity, and this point is emphasized clearly.

What is made clear about the immunity conferred by the letters?

What does the speaker intend to continue doing according to the text?