A man who moved from Ottawa to Fort McMurray less than a month ago was shot dead in his Alberta apartment on Monday, his family told CBC News.

Mustafa Mattan, 28, was answering a knock at his apartment door on Monday night when someone shot through it.

"My brother, he was shot through the door before he even touched the door knob, before he even opened the door," said his brother, Ahmed Mattan, who also lives in the Fort McMurray apartment, along with several other roommates.

"So the killer, whoever he or she might be, they didn't even know who they were killing apart from the fact we were living in that apartment."

Ahmed Mattan said his brother never committed a crime and never hurt anybody.

"He was the nicest, quietest, shyest, most humble person you will ever meet, and he was obviously taken too soon from us," he said.

University graduate

Mustafa Mattan was a university graduate in health sciences who had found work as a security guard in Fort McMurray to save money for a wedding, his brother said.

In Ottawa, Mustafa Mattan was a member of the Assalam Mosque on St. Laurent Boulevard, where people described him as a devout Muslim and a role model who mentored young people.

Childhood friend Mohamud Barre has already crowd-funded more than $4,000 to help the Mattan family cover funeral expenses.

RCMP in Alberta have not confirmed the cause of death. Autopsy results are expected Thursday. Spokesperson Josée Valiquette also said it's too early in the investigation to say what motivated the crime.

In the meantime, the Mattan family is urging whoever is responsible to come forward.

"Please just come forward and tell us why you did this to somebody who didn't deserve to die," Ahmed Mattan said.