The brother of a missing student said Friday he has faith she will be found alive and safe as police continue their investigation.

"I've honestly never lost hope because she is my sister," Marc Kajouji told CBC News in Toronto.

Nadia Kajouji was last seen in her dormitory at Carleton University on March 9.

Nadia Kajouji, 18, was last seen in her dormitory room at Ottawa's Carleton University on March 9.

"It's very uncharacteristic, and that's what's so concerning," he said of her disappearance. He described her as smart and hard working.

"You can say she was sad, you can say she got into an argument with a friend, you can say she broke up with her boyfriend, you can say she couldn't sleep," he said. "But none of that matters because no one really knows her except her close friends and family, so for people to draw their own conclusions is blasphemous."

Meanwhile, Ottawa police are "diligently" investigating her disappearance, Sgt. Uday Jaswal said Friday.

Jaswal said that police are still pursuing leads in the case.

"We're continuing to work diligently on all the information we obtained and hope for a successful resolution in this case," he said.

Kajouji's disappearance wasn't reported to police until three days after she went missing, and there is no indication foul play is involved, he said.

Marc Kajouji talks Friday about the efforts he and his family are taking, including a $50,000 reward, to find his missing 18-year-old sister.
(CBC)

"We're very much looking at any possibility that might arise," Jaswal said, adding police are also looking at footage captured by campus video cameras. "We're looking at all the information and we're not prejudging a conclusion."

Jaswal also said that some people have told police they were concerned about Kajouji's mental state the evening she went missing. Her family has said the teenager was having relationship trouble in the days before she disappeared.

Earlier this week, her parents, who are from the Toronto area, offered a $50,000 reward for her safe return and are considering hiring a private investigator.

"You gotta do whatever you can do," her brother said Friday. "It's a shame to put a price on this girl."