Olivia says that under Megan's law the statute of limitations on the sexual abuse Gretchen and her sister Ellen suffered at the hands of their father would reset if Ellen has repressed memories of the abuse that can be recovered. However, Megan's law has nothing to do with recovered memories or limitation statutes; Megan's law is the informal name given to legislature passed and signed into law on May 17, 1996 that requires law enforcement to make information in the sex offender registry freely available to the public, and to notify the public whenever a registered sex offender moves into a neighborhood.
Even if Gretchen were still alive it would not be a violation of doctor/patient privilege for her psychiatrist to disclose the name of her next of kin to the police since it has nothing to do with her medical conditions or information.