With fears of foul play growing in the cases of three Colorado women who had profiles on small-time modeling websites before they disappeared, an advocacy group for women is launching its own investigation to see if they are connected or possibly even part of a bigger, nationwide case.

The National Women’s Coalition Against Violence and Exploitation has hired a private investigator who plans to look into the possibility of a connection between the disappearances of Raven Furlong, 17, and Kara Nichols, 19, who both had profiles on ModelMayhem.com, and Kelsie Schelling, who has a modeling profile on the site Explore Talent.

“We are considering the options of an independent investigation into not only the cases we are currently handling but other cases that appear to have common attributes that may or may not be linked to the model sites in question,” Shelley Shaffer, head of the coalition's Missing Persons Division, told FoxNews.com.

“We are in conversations with former security investigators among others to see how significant all of the cases are to each other and then we will provide our findings to the authorities. Although we know of many cases with similar connections we are not placing blame on any one site, but we are following the concerns of our clients.”

The coalition and investigators working with it have been probing some 14 cases nationwide in which missing women all had profiles on sites like Model Mayhem.

“When you have so many cases with a common denominator, that’s a red flag,” coalition spokeswoman Michelle Bart said.

Internet Brands, which owns and operates ModelMayhem.com, defended the site's practices in a written statement to FoxNews.com.

"While our policy is to fully cooperate with authorities if approached for assistance in an investigation, Model Mayhem has not been contacted by police authorities regarding either of the three recent disappearances in Colorado," Internet Brands spokesman Joe Ewaskiw said in the statement.

"Model Mayhem strongly believes that safety should be top of mind when doing anything online. ... The site offers detailed safety advice to help members understand what to look for when they are contacted by others," he added.

Site members also are encouraged to alert moderators to suspicious activity.

"Moderators view and respond to each and every inquiry," Ewaskiw said.

But the families of the missing tell FoxNews.com that not enough is being done by Model Mayhem.

“Do they run this website with full disclosure of the risk?” said Julia Nichols, mother of Kara Nichols, who has been missing since Oct. 9. She disappeared after telling her friends she was going to Denver from her Colorado Springs home for a modeling job. “These girls are young and impressionable. If they were fully aware, do you think they would use this website? They should inform the users and have more of a screening process.”

Furlong, 17, has been missing from Aurora since Feb. 5. Police consider her a runaway, according to KRDO. Buckley told Fox 31 Furlong called her family last month, but her mother says the call wasn’t normal.

“She said she had to go because it’s not her phone and they need their phone back,” said Lin Furlong.

Schelling was last seen on Feb. 4. Her empty car was discovered in Pueblo.

Furlong’s aunt, Tobi Buckley, discovered her niece's Model Mayhem profile after she vanished and saw some disturbing correspondence. Buckley has launched a Facebook page to build awareness around the case.

“If they are such a legitimate site, why wouldn’t they do anything?” she said to FoxNews.com. “Bad people are using the site, and they are doing nothing to stop it.”

Police have not officially linked the website—which has an “F” rating with the Better Business Bureau-- to any of the disappearances, but they are aware of the possible dangers that can be associated with using a site such as this.

El Paso County Sheriff's Lt. Jeff Kramer told FoxNews.com the modeling aspect is part of the probe.

“From the onset of the case we were aware that (Nichols) was an aspiring model, and we had a concern about the subculture often associated with these sites,” Kramer said.