Who is Anson Peterson/Anton Brokov from The Key to Midnight and what is their importance?

Anson Peterson is another Mirror project participant. Peterson is also Thomas Chelgrin's contact regarding Lisa. Peterson contacts Chelgrin once a month and arranges a clandestine meeting, where he gives Chelgrin a written report on Lisa's life. For twelve years, this report has been Chelgrin's only contact with his only child. However, after Alex makes contact with Joanna Rand, Peterson informs Chelgrin that Lisa is beginning to realize that she has been brainwashed and that it is necessary to repeat the process. Chelgrin is warned that Lisa might die in the process, but Chelgrin would rather see her die than the alternative, which is to send Lisa to Russia.