ST. JOHNS COUNTY, Fla. -

A St. Johns County deputy whose girlfriend committed suicide two and a half years ago is threatening to sue the Florida Department of Law Enforcement because of the way the agency looked into her death.

Suicide was the official finding in the death of Michelle O'Connell. But an FDLE investigator believed that Deputy Jeremy Banks was involved in the death, and convinced O'Connell's family she'd been killed.

St. Johns County Sheriff David Shoar disagreed. His department had released a report slamming the FDLE investigation, saying the agent turned it into a homicide investigation without regard of any evidence.

Banks and his attorney have filed a claim of negligence against the FDLE.

They say if that is not resolved, they will move ahead with the lawsuit.