Who is used as bait during a police stakeout and how?

During a police stakeout, Dr. Mainwaring is used as bait. Dr. Mainwaring calls Heather and tells her he has information that is important to Jamey's case. He also tells her he wants to sell her the information. Dr. Mainwaring is used as bait in order to catch Heather in her role in poisoning Jamey.