PITTSBURGH — At least one of the those killed in a massacre at the Tree of Life synagogue had been a grade school student in New Jersey.

Robert Gregory Bowers opened fire with an AR-15 rifle and other weapons during worship services on Saturday, killing eight men and three women before a tactical police team tracked him down and shot him, according to state and federal affidavits made public on Sunday. He expressed hatred of Jews during the rampage and later told police that "all these Jews need to die," authorities said.

Dr. Jerry Rabinowitz, 66, was one of those killed. USA Today reported he attended the Maple Avenue School in Newark during elementary and middle school.

His nephew, Avishai Ostrin, in a Facebook post said Rabinowitz was fatally shot after escaping the initial gunfire but returned to tend to those who had been injured.

Flag flies at half mast in honor of the Pittsburgh shooting victims at the Lawrenceville First Aid Station (Dan Alexander, Townsquare Media NJ)

"He was shot outside the room. Why? Because when he heard shots he ran outside to try and see if anyone was hurt and needed a doctor. That was Uncle Jerry, that’s just what he did," Ostrin wrote.

Matthew Lieff in a Facebook post said he and Rabinowitz attended classes in the 1960s at the school, which closed in 2016. It wasn't immediately clear from published reports how many years of his childhood were in New Jersey.

"He and I were the two shortest kids in the class so we were always together at the front of the line. Later I got tall, while Jerry stayed short. But he stood much taller than I did in terms of his accomplishments and impact on his community," Lieff wrote.

Former Allegheny County Deputy District Attorney Law Claus said Rabinowitz was the personal physician for his family.

"He was truly a trusted confidant and healer," Claus said. He said Rabinowitz had an uplifting demeanor and would provide sage advice.

Michael Kerr, on Lieff's Facebook post, Rabinowitz treating him for HIV before there was an effective treatment.

"He was known in the community for keeping us alive the longest. He often held our hands (without rubber gloves) and always always hugged us as we left his office," Kerr said.

Material from the Associated Press was used in this report