The hand-made drawing posted Monday on Reddit by a user called "my secret is out" claims to show where the body of Tamra Keepness is located. She was five years old when she disappeared from her home.
The drawing carries a notation that says "check the wells," although it's not immediately clear where the area in question is located.
Regina police spokeswoman Elizabeth Popowich said authorities are trying to determine whether or not the tip is credible.
"We don't know exactly what it means," she said, adding that what makes this tip different is that it was posted to a public forum.
"Right now everyone is aware of the same information that we have."
Her disappearance on July 5, 2004, sparked a massive search involving hundreds of police and volunteers.
Popowich said police have reached out to the RCMP and the Muscowpetung First Nation, located northeast of Regina, to co-ordinate a response.
"We would be hasty if we just simply ruled it out without looking into it," she said.
She added that over the years police have received close to 1,700 tips related to the case.
"Unfortunately, most of them have been either not been based in any fact, or far-fetched or they've just completely come to a dead end," she said.
Popowich said most people in the province are aware of the girl's disappearance, which has received widespread media coverage.
"You would be hard-pressed to find anyone who hasn't got some memory of this case or perhaps even participated in a ground search," she said.
"There's a great deal of hope every time there is some sort of tip or information, but at the same time we also have to proceed in a fact-based way."
A reward for information leading to Keepness's recovery was raised earlier this year to $50,000.