Jennifer St. Clair, 33, was found dead in the center lane of Interstate 95 in Florida last week. And now her family are suing the man she was on a date with that evening—the man they say left her for dead on that heavily trafficked highway.

The suit came after Miles McChesney, 34, allegedly told authorities he is willing to talk about St. Clair’s death but only if he is guaranteed full immunity. McChesney allegedly fled the scene after St. Clair fell off the back of his motorcycle on their first date.

Authorities have not officially named McChesney in connection with St.Clair’s death, however, declining to comment on the investigation how the Fort Lauderdale woman was found on the highway, her body almost unrecognizable after being struck by multiple cars.

“Our family will never be the same without her. We hope in the coming days there will be justice for Jennifer,” Ashley St. Clair, the victim’s sister-in-law, said, adding that the family hopes their lawsuit will force police to move faster in seeking justice.

In a wrong death lawsuit filed Friday in Broward County court, the St. Clair family alleged that while in town visiting his cousin from New York, McChesney, impaired by alcohol, “carelessly” and negligently drove the motorcycle that caused St. Clair to fall off.

“The only thing we can confirm is that she was a passenger on a motorcycle and ended up on the roadway,” Florida Highway Patrol Lt. Alvaro Feola said Monday. “FHP is still investigating how she ended up on the roadway.”

After meeting on Tinder, McChesney picked up St.Claire, who worked as a waitress, at her home on Dec. 6 at 10 p.m. “with two other couples who also traveled on motorcycles.” The three couples, along with their Harley Davidson bikes, visited three separate bars in downtown Delray Beach.

“While at these establishments, Miles McChesney drank alcohol to the point where he became impaired,” the lawsuit alleged.

At about 2 a.m., the three couples left “Downtown Delray” and headed home, taking Interstate 95 south. St. Clair rode on the back of McChesney’s bike when she was somehow ejected from the motorcycle into oncoming traffic.

“After stopping briefly, but rendering no aid or assistance to Jennifer A. St. Clair, Miles McChesney left the scene,” the suit claimed.

"We don't know how somebody could do something like that. That’s the hardest, hardest part," Amy Gamber, St. Clair’s aunt, said. "My niece was left there. She didn’t deserve that by any means."

Police declined to comment on the lawsuit, its allegations against McChesney, or the autopsy report, citing the “ongoing investigation.”

“The cousin and the other motorcycle driver had gone ahead. When they noticed that Jennifer was not on the bike, the cousin pulled over and called 911,” the family’s attorney, Todd Falzone, said in a press conference.

When McChesney approached his cousin, Bill Young, he told the dispatcher, “Here he is, forget it” and hung up.

After being struck by approximately nine vehicles, the 33-year-old was found by police laying in the highway’s center lane and was pronounced dead at the scene around 3 a.m..

The Broward County Medical Examiner’s Office told The Daily Beast that St. Clair suffered multiple blunt-force injuries, but were unable to determine her cause of death in an initial autopsy and are waiting on pending toxicology test results.

Originally from Schenectady, New York, McChesney was convicted of burglary in 2007 and was sentenced to one year in prison. Five years later, while living in a Horizon House Residential Reentry Center after being convicted of illegal possession of a firearm, he failed to return to the halfway house and was arrested and pleaded guilty to an escape charge, court records show.

Falzone said McChesney was released from prison, this time for violating parole, on Nov. 28, just nine days before St. Clair was found dead.

Following the incident, the New York native obtained a lawyer and immediately requested legal immunity in exchange for full cooperation. That request was not granted because the investigation had just begun.

“At around 10 a.m., within hours of this event, Mr. McChesney’s attorney contacted [Florida Highway Patrol] and said his client would only talk if granted full immunity,” Falzone told reporters at a Friday news conference. “It is my understanding that FHP said they could not do that.”

Feola declined to comment on whether authorities will revisit McChesney’s cooperation deal.

Russell Cormican, McChensey’s attorney, also declined to comment on his client’s immunity request, or if his client is still in South Florida.

"I am representing Myles McChesney in regards to an Florida Highway Patrol Investigation. This is a very tragic event. And this is all I am going to say about it at this time," Cormican said.

Family described St. Clair as a kind soul with an “infectious smile” who always put others before herself.

“Jennifer Amy St. Clair was a loving caring friend, niece, sister, cousin, daughter, and granddaughter whose life was taken way too soon,” Becky St. Clair, her other sister-in-law said. “Jennifer was an avid dog lover and owner. Her heart for her family, friends, and animals showed every day. Her laugh and smile could light up any room.”

Jeremy Chatterton, a friend and former co-worker at Cooper’s Hawk restaurant, who spoke to St.Clair the night she died, described her as the “happiest person he knew.”

“I hope people remember her for the little things she left behind. For the art she made while she was being herself and for the way she inspired people to love all over again,” he said in his speech at her funeral on Saturday.

Chatterton said he heard about St.Clair’s death from a mutual friend the morning after she was found and hopes someone is held accountable for her death.

“I hope there is justice for Jen but nothing will bring her back. Maybe I will feel differently in a month but for right now, I am just in shock she is really gone.”

The lawsuit, which listed McChesney and John Lewis, the bike’s owner who lives in Fort Lauderdale, as defendants, seeks $15,000 in damages and a jury trial.