The father of missing teen Mariam Makhniashvili said the discovery of his daughter's backpack laden with school books is an important step forward in the search for his daughter.

"I also try to not make any bad conclusions yet, because it doesn't mean we can make conclusions about her not being alive," Vakhtang Makhniashvili told reporters outside his Shallmar Boulevard apartment on Friday.

He holds to the view that someone kidnapped Mariam, who will turn 18 on Oct. 27.

"Lots of thoughts are coming right now, but I don't think it's relevant to talk about it right now," added his wife Lela Tabidze, who saw the discovery as good news.

Her voice quavering, she said, "We want to see our daughter -- the faces we see of cheerful children, we want to see her among them," and asked people to come forward if they know anything.

A passerby found the backpack filled with books Thursday afternoon behind an apartment building at 120 Eglinton Avenue East, near Yonge Street. The building is just over two kilometres east of Forest Hill Collegiate, where Makhniashvili was last seen on Sept. 14.

Vakhtang said his family has no link to the location where the backpack was found.

Police echoed the importance of the find.

"This is the first tangible item that we've discovered and so we're always hopeful that something like this certainly would lead us to whereabouts of Mariam," said Det. Dan Nealon of Toronto Police.

In the last month, investigators have given the public a detailed description of the bag and the girl in their quest for clues.

Police say the passerby found the opened backpack on an air vent in the parking lot and picked it up thinking the bag might belong to the girl. When he looked inside, he found Makhniashvili's name written on the books.

Investigators have stepped up their search in the area. About 40 officers on scene will work until nightfall, canvassing the neighbourhood for potential witnesses and security video.

Nealon is asking people who live in the area to take a closer look at the photo of the backpack and the photo of the teen to see if it jogs their memory.

Police believe the backpack may have been there for a couple of weeks under some pine trees, which partially shielded it from the elements. They are doing forensic tests on the pack and its contents. They believe it has been moved from its original location.

Al Nezhadi said he first found the backpack two weeks ago and moved it under a balcony to protect it from the elements. About 20 police officers showed up Thursday night, he told reporters.

"Last night there was like chaos ... I asked them if I can help them. They asked me if I had seen a bag, and I said, 'Yes, it was here,'" he told reporters.

Area residents say they often ignore the frequent unattended backpacks in the area because there are two schools a few blocks away.

Sandy Slater, another area resident, said she's convinced she saw the girl on the first weekend Mariam had gone missing.

"I saw her walking up the street with a guy, a guy probably in his early 20s," she said.

CTV Toronto's John Musselman said police climbed up to a ventilation shaft on a nearby building. They took some items away from there in a white bag, he said, adding police have a set up a command centre.

They will be checking over surveillance camera footage from buildings in the area, he said.

Tough search

Police have tried many techniques to jog the public's collective memory. They released surveillance video of her and her brother at Union Station heading to a dragon boat race on Sept. 13.

They hoped showing video of the teen might help people recognize the girl, but they didn't receive concrete leads.

Nealon revealed his team has received more than 100 tips of possible sightings.

"As you can understand, the resources are strained. To that respect we are trying to run down every lead as possible," he said.

He said they remain hopeful the girl will be found.

Police say they have no evidence showing she ran away or was a victim of foul play. The girl's passport is still at home. Her family said running away would be out of character and that Mariam has not tried to contact friends or relatives back in Georgia.

Their children left the Republic of Georgia for Toronto to reunite with their parents, who had lived in Los Angeles the last five years.

Vakhtang and Lela have mainly stayed in seclusion at their sparsely furnished apartment since their daughter's disappearance.

Mariam is white, 5'3" with light brown, shoulder-length hair and brown eyes. She was last seen wearing black jeans with front and back pockets and buttons as well as a baby blue, long-sleeved v-neck shirt. She was wearing a waist-length blue jean jacket and was carrying an oversized, used black backpack with a silver stripe that was hastily painted over in green.

People with information are asked to contact police at 416−808−5300, Crime Stoppers anonymously at 416−222−TIPS (8477), online at www.222tips.com, or text TOR and a message to CRIMES (274637).

With reports from CTV Toronto's Jim Junkin and John Musselman