Mark Moogalian, the 51-year-old French-American professor identified Monday as the heroic passenger who grabbed the AK-47 weapon away from the gunman aboard a European train on Friday, did “what was right in his heart” and “saved so many,” according to his sister.

“It’s like he was put there [on that train] to stop this horrific massacre,” Mark’s sister, Jacqueline Moogalian Pittman, tells PEOPLE.

“He’s just Mark, he did what came to him instinctively,” she says. “He went into protective mode. It was great. His good human nature kicked in. He was raised by good parents.”

Read the article “Fourth Hero from Paris Train Attacks Identified: French-American Mark Moogalian” on people.com.