Ahmed Shaibi arrived in Brooklyn 15 years ago from the dusty town of Shaeb in Yemen — a place where there the roads are unpaved and most families make their living tilling the earth. Jobs were hard to find, and his father was making a decent living in New York, so the trip west was a way to provide for his two small children and wife, relatives said.

That dream came to a close late Sunday night when a man wearing a hooded sweatshirt shot him at point blank range in the head during a robbery, killing him instantly.

Shaibi, who also went by “Ali,” worked 12 hours a day as a cashier at Minimart on the corner of Nostrand Avenue and Avenue R in the Sheepshead Bay section of Brooklyn. He was behind the register when two men entered the store and demanded he give them money. The police said another man waited outside as a lookout.

Hussein Saleh was also working at the delicatessen on Sunday night, but he was in the back of the store with another employee. When he heard a commotion, he came to the front and found Shaibi “scuffling” with the two men, according to Mr. Saleh’s sister, Hanea Saleh, 23.

“Ahmed was yelling,‘ Call the police, call the police,’ in Arabic,” Ms. Saleh said.

Mr. Saleh ran to the back to get to a phone, but by the time he returned he found Shaibi slumped behind the register. Blood was coming out of his head, his face was blue, and his eyes were closed and swollen, she said.

It wasn’t long before a helicopter’s rotor beat over the neighborhood and dozens of police officers were on the scene, observers said, but the thugs got away. No arrests have been made.

The police said they are investigating whether the hooded trio was connected to a pattern of 10 to 15 similar robberies in Brooklyn over the last several months.

The store, which rarely closes for more than four hours, was shuttered yesterday. Residents and regulars gathered on the streetcorner to discuss the shooting. A makeshift memorial formed, with flowers, candles, a stuffed rabbit, and a sign that read: “We will miss you Ali / Rest in peace our friend.”

“I couldn’t sleep last night,” a woman who visited the store often, Marsha Kaplan, said through tears. “Everybody is devastated on my block. It’s like a family member died.”

Shaibi worked 1 p.m to 1 a.m. every day of the week. His schedule, according to a friend who works at a deli on Avenue U, Fiasal Mohamed, 37, left only about 20 minutes a day for the two to visit and drink Yemeni coffee.

“He would go home, take a shower, pray, and go to sleep,” Mr. Mohamed said.

He lived with his stepmother, Muntaha Shaibi, and three younger brothers on East 15th Street. Since his father died eight years ago, Shaibi supported them, as well as his wife, daughter, and son in Yemen, on his small salary.

Ms. Shaibi, who was lying down and dressed in a traditional Muslim hijab at her apartment yesterday, said her son was the keystone of the family. (Her age is not known because she never kept track, she said. Family members estimated she is between 55 and 60.)

“She said when she heard the news, she wished it was her instead of him,” a family friend, Fairoz Hussein, 32, said, translating Ms. Shaibi’s comments. “Now she has no support. What is she going to do?”

A second cousin of Shaibi, Mason Mohammed, 31, said a network of Yemenis in the area would likely take care of the family for the time being.

“They took away the life of an important person,” he said. “By taking away his life, they affected a lot of peoples’ lives.”