KNOXVILLE, Tenn. (WOKI / WVLT) – One of the highest-profile defendants in the Knox County Sheriff’s Office conspiracy case is asking a judge to prevent prosecutors from using statements he made to federal investigators, arguing he was effectively forced to cooperate without being advised of his rights as a law enforcement officer.
David Amburn, a longtime Knox County Sheriff’s Office captain who later served as Chief of Detectives and ran for Knox County sheriff, filed a Motion to Suppress Statements on Oct. 12 in Knox County Criminal Court.
The motion seeks to exclude statements Amburn made during four interviews with FBI investigators as well as evidence he later provided during the investigation.
Amburn is among 11 current and former Knox County Sheriff’s Office employees charged with conspiracy to commit theft over $250,000, theft of property over $250,000 and theft of services. Prosecutors allege the defendants misused sheriff’s office funds and law enforcement resources between 2011 and 2018. All defendants have pleaded not guilty.
Defense Cites Garrity Protections
At the center of Amburn’s motion is the U.S. Supreme Court’s 1967 decision in Garrity v. New Jersey, which protects public employees from being forced to choose between keeping their jobs and exercising their Fifth Amendment right against self-incrimination.
According to the filing, Amburn believed refusing to cooperate with federal investigators could have jeopardized his employment with KCSO. His attorneys argue that because departmental policies required deputies and supervisors to cooperate fully with investigations, any statements he provided should be considered compelled and therefore inadmissible in court.
The motion states Amburn was interviewed by FBI investigators on four occasions:
- April 9, 2020, at Malibu Auto Body Repair on Maynardville Pike
- April 27, 2020, at the KCSO Asset Lot on Bernard Avenue
- May 29, 2020, during a telephone interview
- February 19, 2022, during a second telephone interview
Court records also indicate Amburn provided photographs and other materials to investigators during the course of the federal probe.
His attorneys contend neither the FBI nor KCSO provided Garrity warnings before the interviews took place.
Sheriff Spangler Affidavit Cited
The filing relies heavily on an affidavit submitted earlier by former Knox County Sheriff Tom Spangler.
According to the motion, Spangler stated KCSO cooperated fully with the FBI investigation and maintained regular contact with agents. The filing also notes Spangler later promoted Amburn to Chief of Detectives and endorsed his campaign for sheriff, actions the defense says demonstrate there was no indication Amburn should view himself as a criminal target rather than a cooperating employee.
Amburn is requesting an evidentiary hearing where he plans to testify that he believed remaining silent could have endangered his career with the sheriff’s office.
Similar Motions Filed by Other Defendants
Amburn is not the only defendant making the argument.
Three co-defendants have filed nearly identical motions seeking to suppress statements made during FBI interviews:
- James Hammond, a KCSO captain, seeks to exclude statements from interviews conducted in April 2020.
- Lake Lowry, a former sergeant, argues FBI records do not show Garrity or Miranda warnings were provided before his interview.
- Curtis Cole, a former narcotics detective, claims he was told by KCSO leadership that cooperation with investigators was expected.
Each defendant is asking the court to suppress statements and evidence obtained through those interviews and to hold hearings on the issue before trial.
The motions represent one of the latest legal challenges in the high-profile corruption and theft case that has drawn significant attention across Knox County and could shape what evidence prosecutors are ultimately allowed to present to a jury.

11 current and former Knox County Sheriff’s Office employees charged with conspiracy to commit theft over $250,000, theft of property over $250,000 and theft of services (wvlt)








