Pennsylvania Gov. Josh Shapiro (D) announced on Thursday that he will not sign any execution warrants as governor and called for the state legislature to abolish the death penalty.

“When an execution warrant comes to my desk, I will sign a reprieve each and every time,” he said at an event in Philadelphia.

His announcement follows the precedent set by former Pennsylvania Gov. Tom Wolf (D), who issued a moratorium on executions during his first year in office in 2015. Wolf similarly granted reprieves to death row prisoners at risk of execution.

Shapiro, who previously served as the Keystone State’s attorney general, said on Thursday that his views on the death penalty have evolved over time.

“For more than a decade, including when I assumed office as Attorney General, I believed that the death penalty should be reserved for the most heinous crimes — but that it was, indeed, a just punishment for those crimes,” he said.

The Tree of Life shooting in 2018 was particularly influential in his shift on the issue, Shapiro added. A gunman opened fire in a Pittsburgh, Pa., synagogue in October 2018, killing 11 people.

“It’s hard to imagine a more heinous crime than murdering 11 people as they pray. And candidly, my first reaction was that the killer deserved to be put to death,” he said. “Over time, however, my belief on this topic has evolved.”

Despite their losses, the victims’ families reportedly told Shapiro that they did not want the killer to receive the death penalty. The alleged shooter, Robert Bowers, is set to stand trial this April, more than four years after the shooting occurred.

Shapiro also noted that as attorney general, he became increasingly aware that the capital sentencing system is “fallible” and has “irreversible” consequences.

“The Commonwealth shouldn’t be in the business of putting people to death. Period,” he said. “I believe that in my heart. This is a fundamental statement of morality. Of what’s right and wrong.”

“I believe Pennsylvania must be on the right side of this issue,” Shapiro added.

Twenty-three states and Washington, D.C., have abolished the death penalty, according to the non-profit Death Penalty Information Center.

Pennsylvania is one of three states, alongside California and Oregon, to have a moratorium on executions issued by the governor. Attorney General Merrick Garland also issued a federal moratorium in July 2021.