Updated

A psychiatrist who treated school shooter Adam Lanza years before the Sandy Hook Elementary School massacre in Connecticut voluntarily surrendered his medical license in July 2012 amid allegations he had a sexual relationship with a female patient, according to public records released Monday.

Dr. Paul L. Fox, a former Brookfield, Conn., psychiatrist now living in New Zealand, told police investigating the school shooting that he vaguely recalled treating Lanza. He told police he last saw Lanza when he was about 15 years old and remembered him having aggression problems and possibly Asperger's syndrome, a form of autism not associated with violence.

Lanza was 20 years old when authorities say he killed 20 first-graders and six adults at the Newtown school in December 2012. He first shot his mother to death at their Newtown home before going to the school, where he killed himself as police arrived.

Authorities have not raised any questions about Fox's treatment of Lanza.

In May 2010, Fox began treating the female patient who later would allege that she and Fox had a consensual sexual relationship for over a year, according to a draft investigative report by the Connecticut Public Health Department.

The woman alleged she and Fox had sexual encounters in his office, went out to eat together and spent time together on Fox's sailboat, according to the investigative report. The draft report found that Fox's interactions with the woman exceeded the boundaries of a "professional doctor, patient relationship."

Fox settled the claims by voluntarily surrendering his Connecticut medical license and did not admit any wrongdoing. He also surrendered his New York medical license, records show.

Fox having surrendered his license was first reported by the Connecticut Post.

Hartford lawyer Richard Tynan, who represented Fox during Connecticut investigation, said that he was not aware that Fox was involved in Lanza's treatment.

"Never having discussed anything else with Dr. Fox other than that one matter, I can't see how in any shape or form it can be related to the unfortunate events in Newtown," Tynan said Monday.

Contact information for Fox in New Zealand couldn't be found.

According to Connecticut State Police documents released Friday, Fox told investigators that medical records he kept on Lanza had been destroyed, as allowed by state law, because it had been more than five years since he last treated him.

Fox told police that Lanza was very rigid and resistant to engagement. He said he couldn't provide any other details about Lanza.

It remains unclear why Lanza wanted to kill children at the school. Authorities said they found disturbing, violent writings by Lanza and evidence that he was interested in mass killings and played violent video games.

Lanza was diagnosed by another psychiatrist as having "profound Autism Spectrum Disorder" and symptoms of obsessive-compulsive disorder. A nurse who prescribed antidepressant and anti-anxiety medication for Lanza said her recommendations were not followed by Lanza's mother, who kept legal guns in her home.