David Runk, Associated Press
Clayton Carter, owner of Can You Picture This, holds a T-shirt made in memory of Demesha Hunt, 24, left, and Renisha Landers, 23, right, on Tuesday, Dec. 27, 2011, in Detroit. Hunts' and Landers' bodies were found Dec. 19, 2011, in a car trunk in Detroit. Police discovered the badly burned bodies of two other women on Sunday, Dec. 25, 2011, in a car trunk. Police have said three of the four women had promoted themselves as escorts through the same website.

DETROIT — Detroit police fear that a killer may be targeting escorts after finding that three of four women found dead in car trunks within blocks of each other this month had placed sex-related ads on the same website.

Attorneys general for 45 states had raised concerns earlier this year about how the site, Backpage.com, polices ads for adult services.

Police Chief Ralph Godbee said authorities find the link "disconcerting." The deaths could be connected, Godbee said, though he has said police were "stopping short" of calling it the work of a serial killer.

"The link between the three females and this website specifically dealt with prearranged adult dating services," Godbee said Monday.

The latest victims were found Christmas morning, when Detroit firefighters discovered their badly burned bodies in the trunk of a car that had been set ablaze in a garage. They were identified as women ages 28 and 29, and police were awaiting a determination from the medical examiner's office on the exact cause of death.

Meanwhile, the families of Demesha Hunt, 24, and Renisha Landers, 23, whose bodies were found Dec. 19 in the trunk of a car parked in the driveway of a vacant home on the city's east side, prepared for a joint funeral Thursday. The Detroit women had been reported missing by relatives after they didn't return from a night out and police said there were no outer signs of trauma to the bodies.

"This is a tragedy for our family," Hunt's mother, Denise Reid, told WJBK-TV. "It could be a tragedy for yours one day, so if you know something, then just speak up."

Relatives of Hunt and Landers did not immediately respond to messages from The Associated Press.

The names of the latest victims hadn't been released Tuesday. Police also haven't said which three of the women had had promoted themselves as escorts on Backpage.com, which is used to buy and sell things but that also carries personal ads.

A Backpage.com lawyer didn't immediately respond to email and phone messages seeking comment.

Paul DeCailly, a Tampa, Fla.-based attorney who represents escort services in court, said he doesn't believe that Backpage.com could be held liable for providing a service that brings people together. He said that that a newspaper, for example, wouldn't be held liable for a personal ad placed in its pages.

"I don't think that throwing in the term 'escort' in this particular situation changes the outcome of potential liability," DeCailly said.

He noted that the killings come amid government efforts to stamp out the use of the Internet for arranging escorts.

"Whoever did this, regardless of where he found his victims, was going to do the same thing," DeCailly said. "The question is when they catch him is he going to be someone who even had access to the Internet."

The attorneys general of Michigan and Illinois were among those across the country who wrote Backpage.com on Aug. 31 demanding that it show it was not promoting illegal sexual activity. Attorneys general and others had raised similar concerns about Craigslist, which agreed to close its adult services section last year.

Email and phone requests for comment were left Tuesday for attorneys general in Michigan and Illinois.

James Alan Fox, a criminologist at Northeastern University in Boston who has written about serial killers, said Detroit police could be dealing with a case of a serial killer or a copycat double-killing. Because the bodies were found in pairs it's possible, he said, that more than one person was involved.

He said the women may have been killed elsewhere and their bodies dumped, a common way that serial killers operate. He noted that online ads for escort services are risky for those involved because they're dealing with strangers. And he said the police warnings for caution might not be heeded.

"Even when a perpetrator is known to be on the on loose, many women will put profit over protection," Fox said.

Detroit police said Tuesday they had no new developments in the investigation to report.

On Tuesday, printing business Can You Picture This in Detroit made T-shirts in memory of Hunt and Landers. Money from the sale of the shirts was to go to their families, said owner Clayton Carter.

Near signs promoting printing for business cards, banners and Christmas cards for the just-passed holiday, three adult-sized shirts in memory of Hunt and Landers sat on a counter along with an infant's shirt showing Hunt and her young daughter, their photos in a heart with red roses.

"It's disturbing to have this kind of stuff going on in our city," Carter said.

Associated Press writer David N. Goodman contributed to this report.