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

Christal Hayes | USA TODAY

Show Caption Hide Caption Teen voices stand tall during the March for Our Lives Protesters explain why they’ve had #enough and give their thoughts on gun control during the March for Our Lives in Washington, D.C., March 24, 2018.

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.

Who is this person? Around 12:40 p.m. July 17, our homicide detectives say he robbed and killed Ayub Ali at Aunt Molly's Food Store in North Lauderdale. pic.twitter.com/2VDoztwWnP — Broward Sheriff (@browardsheriff) July 19, 2018

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.

Follow Christal Hayes on Twitter: Journo_Christal