The son of a woman whose body was found alongside a Meigs County sheriff's deputy in the Tennessee River filed a federal wrongful death lawsuit blaming the Meigs County government for his mother's death.

Nathan Smith filed the suit on behalf of his deceased mother, Tabitha Smith, on Monday in the Eastern District of Tennessee. The 16-page suit claims the deceased deputy, Robert "R.J." Leonard, was not "properly trained by the county to know his assigned area of patrol and know the nature of the incident location."

"The location of the incident has a history of other people driving into the Tennessee River," according to the suit.

Smith is demanding a jury trial and seeking a $10 million award for damages caused by the violation of his deceased mother's constitutional rights, the suit says.

USA TODAY contacted Meigs County but did not receive an immediate response.

"Leonard’s inexplicable acts and omissions, despite his duty to protect the deceased, resulted in the constitutional deprivations, physical harm, and the indignity and humiliation of the loss of life and bodily integrity as she died while handcuffed in the back of the patrol car," according to the suit.

Leonard was texting, driving before the drowning, Smith alleges

Leonard took Smith into custody Feb. 14 after being called to a disturbance on the Tennessee Highway 60 bridge, which spans the Tennessee River, according to the suit. It took three minutes for Leonard to handcuff Smith and put her in the back of his patrol car, the suit continued.

At some point between the arrest and the incident, Leonard sent his wife a text, the suit reads. Leonard's last breath may have come when he used his radio to tell the police dispatcher for the county, "Water," according to the suit.

When authorities found Leonard's patrol car, it was flipped upside down at the bottom of the Tennessee River.

"The vehicle was nose in, but upside down, wheels up," District Attorney General Russell Johnson said at a press conference after the incident.

What to know:Bodies of Tennessee deputy, woman he arrested found in Tennessee River

Johnson also said Leonard's wife, Christina, received a one-word text message from the rookie deputy that read "arrest." She responded to the text, though his phone never got the message, he said.

"As a direct and proximate result of the acts and omissions of Leonard and the county, the deceased suffered a horrific death," the suit says.

Smith, Leonard survived by their children

Tabitha Smith is survived by one adult child, Nathan, and three minor children, according to the suit.

"As a direct and proximate result of the acts and omissions averred herein, (Nathan Smith) lost his mother, lost any future he may have had with his mother, lost his ability to have a continuing relationship with his mother," the suit reads.

Authorities are continuing to investigate the incident to determine what happened, Johnson said.

“We’re operating under the theory that it was an accident, he missed his turn, he wasn’t familiar, and he was doing other things that may have caused him to go into the water,” the district attorney general said. “There’s some skid marks and some scratch marks, too. So, there’s some indication that he was on the brakes at least trying to stop.”

Leonard, who had been with the sheriff's department for two months, is survived by his wife and five children, according to his obituary. His funeral was held Feb. 19.

The Police Benevolent Foundation set up a memorial fund to help Leonard's family during this time.

Jonathan Limehouse covers breaking and trending news for USA TODAY. Reach him at [email protected].