The agreement with the University of Pittsburgh Medical Center allows the Allegheny County district attorney's office to see John Shick's medical records. But the DA can't share the records with the public without further court orders.
Shick, 30, was slain by police after the March 8 shootings at UPMC's Western Psychiatric Institute and Clinic, and investigators have been trying to determine his motive and relationship to the clinic.
Shick's parents made their first public comments on Thursday. They had been sailing in the Bahamas, and the Coast Guard helped contact them.
Larry and Susan Shick told The Pittsburgh Tribune-Review in an email that they've "been cooperating with the authorities investigating this terrible event." The Shicks said they "share the grief and pain of the victims and their families, and we hope that they, and the press, will respect our grief, pain, and privacy."
The parents of the man Shick killed are questioning whether the clinic had adequate security. Authorities have said it appears that 25-year-old nurse Michael Schaab was in the clinic lobby by chance when Shick entered and began shooting.
Mary and Harry Schaab expressed compassion for Shick in an interview with the Pittsburgh Post-Gazette and said their son would have wanted to help him.
But the Schaabs questioned security at the clinic, and whether Western Psychiatric let a mentally ill man fall through the cracks.
Mary Schaab told the paper that she felt the shooting could have been prevented with better security at the clinic's entrance.
Authorities have said Shick had mental illness and perhaps physical ailments before the shootings. They had sought his medical records to better understand the shootings.
Shick used two semiautomatic pistols as he marched around checking offices at the clinic, possibly in an attempt to find more victims. He also had a fanny pack containing plastic bags with medicines and carried extra ammunition.
Shick had been enrolled as a graduate biology student at nearby Duquesne University but was banned from campus and withdrew after female students brought harassment complaints against him last fall.