Police investigate YouTube video in teenage girl's 2009 disappearance

ANTIGO, Wis. (WLS) -- A viral video is giving hope to the family of a long missing teenage girl in Wisconsin.

The FBI and police in Wisconsin are asking if it's Berg in a disturbing Facebook video of a man keeping a young girl captive in his basement. Berg was 15 when she vanished in August 2009 after being dropped off at a friend's house.

In one point in the video, a young girl that some believe may be Kayla Berg, is seen tied up on the bathroom floor, sobbing and screaming. Even though it was posted in 2009, the video only recently went viral and came to the attention of police in the teenager's Wisconsin home town.

"We're still trying to identify the subject in the video. Obviously the male would be good to identify that. If we could talk to him identify who it is, find out where that video was posted from, that is going to be out best bet to begin with," Antigo Police Chief Eric Roller said.

The video is called "Hi Walter! I got a new gf today!" "GF" is the popular abbreviation for girlfriend. The missing girl's mother has renewed hope that these new clues will lead to her daughter.

"Sounded like her, looked like her. It gave me chills. It's hard to explain. That first initial thought is, that's my daughter. But I don't know that. I don't know if it's real. I don't know if it's fake. My God it could be some other person's child or missing loved one. Or if it's fake, this person has an extremely sick sense of humor," Hope Sprenger, Berg's mother, said.

On Facebook the video recently went from a few thousand views to almost a million. But it was taken down by Facebook on Tuesday because it violates the website's standards.

Police are not happy about that because they say potential leads could disappear.

While the video was posted, some Facebook users named someone they thought looked like the suspect. Police quickly cleared him and asked that he not be harassed.

The FBI office in Milwaukee issued the following statement on the case Tuesday: "The FBI has been assisting Antigo Police Department in the Missing Person case of Kayla May Berg, since 2009. The FBI continues to work with the Antigo PD, as they determine whether or not a video that was posted on YouTube has anything to do with the disappearance of Kayla Berg."

The FBI continues to offer a $20,000 reward for information leading to the arrest and conviction of the person or persons responsible for Berg's disappearance.

ABC News contributed to this report.