There is a billboard asking "Injured by a Chiropractor" that is making its way around Bridgeport and to many it is a mystery who is behind it.

It also is giving chiropractors in Connecticut and around the country a real pain in the neck.

The chiropractic industry wants to know who is behind the ads on a Bridgeport bus which targets the profession.

Tonight, Team 8 investigator Alan Cohn reveals who is taking out the ads and why.

On their website, the president of the World Chiropractic Alliance likens the ad to a hate crime and he warns if those bus signs aren't taken down immediately, the WCA is prepared to go to federal court and give them an adjustment they won't forget.

But the president of the Greater Bridgeport Transit Authority says this is a matter of free speech.

It's a rhetorical question on one bus in one city but it's got chiropractors from Connecticut to California more than just a little upset.

"Who in their right mind would do something like that especially with a false message."

"Injured by a chiropractor?" the ad on a Greater Bridgeport Transit Authority bus asks, while pictures show two women grimacing in the clutches of a chiropractor.

The ad is sponsored by the Chiropractic Stroke Awareness Group.

Luigi DiRubba is a chiropractor in Cheshire and the Connecticut representative of International Chiropractors Association.

"We are talking about individuals out there that may read this slanderous statement and may misconstrue it. There is a major issue here," says DiRubba.

But DiRubba's reaction pales in comparison to the response of the World Chiropractic Alliance. The group's attorney is demanding the Transit Authority remove the ad calling it "shameless and legally libelous," and "a vicious attack."

Ron Kilcoyne is the Transit Authority's C.E.O. and has been deluged by calls, letters, and emails from angry chiropractors but says, "This ad was not slanderous. It asked a rhetorical question. Have you been injured? It did not specify any particular chiropractor. It did not make any statement of fact."

The World Chiropractic Alliance is also asking the Transit Authority to provide it with a copy of the agreement for the ad. The organization doesn't know who is responsible for it, but we do.

"It is us. It is a group of victims, family members and friends who have been traumatized by this. Whose lives have been destroyed," says Britt.

Britt, who asked us not to use her last name, says she reached an out of court settlement after having a stroke just over three years ago in her chiropractor's office.

"His hands were still touching my head when I felt this horrendous rushing sensation and heard a noise in my head," says Britt.

Britt continues to receive physical therapy. She requires a feeding tube because she's lost the ability to swallow.

"She heard herself screeching."

Britt's injuries are not nearly as serious as 56-year-old Linda Solsbury, a former nurse who suffered a stroke during an adjustment 20-years ago. She says she won a multi-million dollar jury award. She's partially paralyzed, can't speak and must use a keyboard to communicate.

She told us why she is involved in the ad campaign.

"To find people in our state who have been through this in varying degrees and to come out because there has been enough to validate the reasons for doing this," says Solsbury.

The women point to the World Chiropractic Alliance's own literature which says "numerous published scientific and medical studies indicate incidence of stroke is estimated at between 1 to 3 incidents per million adjustments.

"When we are talking about risk factors our profession is at a very low level," says DiRubba.

Some of Dr. DiRubba's patients, like 66-year-old Bruce Franklin, say chiropractic adjustments have made a huge difference in their lives.

"I have no fear at all and I've never been hurt," says Bruce Franklin, Wallingford.

The attorney representing the World Chiropractic Alliance told us late today the organization is preparing to take appropriate action including filing a lawsuit. They are also investigating who is behind the ads. Now they know.