In written testimony before his death, former Knox County Sheriff Tom Spangler said he was told repeatedly by FBI agents that only retired assistant chief David Henderson was the subject of their investigation into corruption in the sheriff's office.
And that was true. The FBI sought charges in February 2022 from its investigation against only Henderson, who awaits sentencing for his guilty plea on a single federal count of conspiracy to commit program fraud.
But once the FBI concluded its investigation, agents handed over their files to the Tennessee Bureau of Investigation, which targeted a much wider group of Knox County Sheriff's Office employees.
Some of those targeted employees gave statements to the FBI, which the TBI then used to charge
11 people associated with the sheriff's office. Included among those charged are some of the KCSO employees who talked to the FBI.
Two of the indicted men, former Assistant Chief Deputy David Amburn and former Sgt. Lake Lowry, argue prosecutors shouldn't be able to use statements they made to FBI agents who were investigating Henderson.
It's another turn in one of the largest law enforcement corruption crackdowns in Tennessee history.
Previous statements from KCSO officers under scrutiny
When Amburn and Lowry agreed to speak with the FBI in multiple interviews in 2020 about Henderson's actions, they did so because it was required of them through a department policy, they say in new filings.
Allowing the statements to be used against them in court could violate their Fifth and Fourteenth Amendment rights, along with state law, their attorneys argued. The Fifth Amendment protects a person from self-incrimination and guarantees due process, and the Fourteenth Amendment also guarantees due process.
Had Amburn and Lowry known the TBI would later use those conversations to request indictments against them on state charges, they would have treated the interviews differently.
“Mr. Amburn was expected to cooperate with the Federal Bureau of Investigation’s investigation and faced the predicament of whether to risk his employment situation with silence or risk his freedom with cooperation,” Amburn’s attorney Stephen Ross Johnson said.
Lowry made a similar argument. His attorney, Melissa DiRado, called it a “penalty situation.”
Both men say they face violations of their rights – called Garrity rights – that protect public employees' statements made under the express or implied threat of job loss.
What do KSCO rules say?
Amburn and Lowry's argument will come down to whether their jobs were on the line if they didn’t speak with federal investigators, said Vanderbilt University professor Christopher Slobogin, who is director of the university’s Criminal Justice Program.
“(Were they) believing they’d lose their jobs if they didn’t talk? If I were the defense that’s (what I’d argue),” Slobogin told Knox News. “If I’m the state, I’d argue they talked not because they thought they’d lose their job but because they were cooperating with the police.”
If wasn't explicit that they were putting their jobs in jeopardy by not talking to the FBI, Slobogin said, it likely isn’t a Garrity violation. Garrity generally bars prosecutors from using statements a public employee was compelled to give under threat of losing their job.
“’I’m not in trouble, only my boss is.’ I can see why he feels that way, but that doesn’t matter,” Slobogin said. “If he says something incriminating … police use incriminating statements by people who don’t know they’re being investigated all the time.”
Don Cochran, former U.S. attorney of the Middle District of Tennessee, told Knox News he thought the motion could have standing if the men weren’t given any type of Garrity warning. It wouldn’t matter that there was a different agency taking the statements from the one that brought the indictments, he said.
The sheriff’s office policies at the time, according to the filings, don’t lay out direct consequences for not cooperating with investigations, nor did they explicitly protect their Fifth Amendment rights during outside criminal investigations.
The policy, according to the filings, says:
- “It is the responsibility of members of this agency to respond truthfully when interviewed by supervisors or investigators in connection with an official inquiry.”
- “All personnel will work and cooperate fully with all other law enforcement, judicial or corrections agencies to assist them in any manner during official law enforcement functions.”
While only Amburn and Lowry are asking to suppress their statements to the FBI, several other of the indicted men spoke with federal investigators and could choose to enter a similar request to Senior Judge Don R. Ash.
Another joint motion to dismiss
Separately, all 11 defendants filed a joint motion Oct. 9 to dismiss the charges, arguing prosecutors did not adequately explain the actions each man took individually to lead to charges.
Prosecutors charged the 11 men with conspiracy and generally laid out their case. But charging documents do not detail specific dates, times or actions tying individuals to allegations, nor did they explain how the actions are connected. The charges are more of an aggregation than specific accounting of allegations.
Because of the broad description, the defendants argue, the case should be tossed.
“The overt acts have little in common, and allege fundamentally different activities, for different objectives, benefitting different people, and committed by different means," the filings say.
Ash is expected to address these motions, among others, at the group's next scheduled hearing Nov. 3.
How the KCSO corruption case unfolded
The indictments stem from yearslong federal and state investigations into the department's troubled narcotics unit. A federal investigation resulted in the conviction of Henderson, the unit's former leader, on a single federal count of conspiracy to commit program fraud.
The TBI picked up the work, and its investigation led to state charges of conspiracy to commit theft of property over $250,000; theft of property over $250,000; and theft of services over $60,000 for all 11 men. Each one entered a not guilty plea.
All the charges are felonies and all have potential serious prison sentences:
- Conspiracy to commit theft of property over $250,000: 8-12 years
- Theft of property over $250,000: 15-25 years
- Theft of services over $60,000: 8-12 years
The indicted men are:
- Assistant Chief Deputy David Amburn, who oversaw the sheriff’s office narcotics unit
- Curtis Nathan Cole, a former narcotics unit detective
- Capt. James Hammond
- David Henderson, a retired KCSO assistant chief deputy, who pleaded guilty to a single count of conspiracy to commit federal program fraud in August 2025. His sentencing hearing has been rescheduled several times and is now scheduled for this fall.
- John "Hoppy" Hopkins, a retired KCSO captain
- Sgt. Timothy Isaacs
- Jimmy "J.J." Jones, a former Knox County sheriff
- Michael Ray Kidd, a civilian. Kidd's brother is Ronnie Kidd, a former KCSO fleet manager who pleaded guilty to a felony charge of official misconduct in October 2020 and was sentenced to two years of probation.
- Lt. Franklin "Rocky" Lowery
- Lake Lowry, a former KCSO sergeant
- Capt. Aaron Yarnell, who supervised the agency's technology division.
Tyler Whetstone is an investigative reporter focused on accountability journalism. Email: tyler.whetstone@knoxnews.com; X: @tyler_whetstone; Signal: twhetstone141924.39
This article originally appeared on Knoxville News Sentinel: KCSO suspects argue handoff from FBI to TBI violated their rights | Exclusive
