Working the overnight shift at Trax Food was clerk Mustafa Shaker's second job. The Egyptian native, 50, who came to the States almost 20 years ago, drove a Philadelphia cab by day. On weekends, he'd visit his two teenage children, who live in the Poconos with their mother.

He was robbed at gunpoint about three years ago while working nights at a Frankford Avenue Quick Stop. He gave the robbers $150 from the drawer without a fight, a former coworker said.

Early Thursday morning, in footage caught on a surveillance camera, two unidentified young men strutted into Trax, a 24-hour convenience store under the El at Front and Girard. where Northern Liberties. Kensington and Fishtown converge. One of the men pulled a sawed-off shotgun from under his sweatshirt and thrust it in Shaker's face.

This time, Shaker, an Egyptian Army veteran, resisted. Standing behind the counter, in front of the cigarette racks and shelves of soaps and shampoos, he pleaded with the gunmen to leave as they hit him with the barrel of the shotgun. He pushed the register closed, the video shows.

The gunman shot him in the head. Then the would-be robbers tried to pry the register from the counter. They left with nothing.

"A vicious killing," Homicide Capt. James Clark said at a news conference where police released the security footage.

The shooter, who is black and believed to be in his early 20s, was wearing a gray sweatshirt and black baseball cap with Armani printed in on it, police said.

The second suspect, also black, was wearing a sweatshirt with a Nike swoosh and a watch with a pink or red band.

On Thursday morning, Shaker's brother, nephew, and friends gathered on the sidewalk in front of the store. Mohammed Eman said it was not in his uncle's character to fight off his attackers.

"He was a peaceful man," said Eman, who had just come from Shaker's apartment, where he'd gone to collect his uncle's personal papers.

From a manila envelope, Eman pulled out drawings for a website that Shaker, a Muslim, was developing. The site, called Hearts of Religions, was aimed at promoting unity among faiths, Eman said.

Shaker had hung posters about his project behind the counter in the store.

"He was excited about it," Eman said. "He always wanted to be something more in life."

Morhaf Sheikh Yousef worked alongside Shaker when he was robbed at the Frankford store. He didn't know why his friend did not just hand over the money.

"Even if he got yelled at in the morning for it," Yousef said, "that's all that would happen."

Neighbors remembered Shaker as a friendly man who liked to make small talk about the characters in the neighborhood and the recent upheaval in Egypt.

"He was someone you saw every day, a cool, even-tempered guy," said Alaina Wray, 29, who lives above the store.

Shaker had worked at the store for about three months, the owner said.

Three weeks ago, he moved from North Philadelphia to an apartment two blocks from the store so he could be closer to work. The walls were still mostly bare, Eman said.

"Except for photos of his children."

Contact staff writer Mike Newall at 215-854-2759 or mnewall@phillynews.com.