Two Parkland students survived a school shooting. Then their father was shot and killed.

The father of two students who survived the shooting in Parkland, Florida, was shot and killed this week during a store robbery.

Ayub Ali, the owner at the Aunt Molly's Food Store convenience store in North Lauderdale, was killed in a robbery that turned violent Tuesday afternoon.

Ali, 61, was the breadwinner of his family and a father to four children, including two who attended Marjory Stoneman Douglas High School, the site of a February mass shooting that left 17 dead.

"It tears me up that this happened," friend Joaquin Nieves told CBS Miami. "I hope that someone who saw something will call the cops. I mean stop the violence."

Ali, who had settled in South Florida after moving from Bangladesh, had encouraged his daughter to advocate for gun-control changes after she and her brother survived the Valentine's Day massacre at their high school.

Elama Ali, 16, told CNN her father encouraged her to travel to Washington, D.C., for "March for Our Lives" to push for gun law changes.

"When I was in Washington, he asked about it. He watched it on TV," she told CNN. "We're trying to be strong, but it's overwhelming."

Broward County deputies say Ali was working behind the cash register when a man entered the store with a gun and demanded cash. After leaving with the money, he returned to shoot and kill Ali, authorities said.

That detail is what is leaving his family to question why this happened.

"If you came for the money, take the money and go,"  Ali's wife, Farhana, told CNN. "Why did you have to kill my husband?"

The Broward County Sheriff's Office has asked for the public's help in identifying the man they say was caught on surveillance footage robbing the store. No arrests have been made.

WFTV