Officials believe Davis intentionally injected air into arterial lines of patients recovering from heart surgery, causing them to have stroke-like symptoms. Hospital officials initially informed law enforcement of seven suspicious and/or unexplained incidents. 

Davis worked for Christus Mother Frances Hospital-Tyler for five years and was terminated Feb. 15, about a week after hospital officials went to police with their concerns. Prior to that, he worked for Christus Good Shepherd Medical Center in Longview from 2011 to 2013. All the incidents included in the arrest warrant affidavit occurred at Christus Mother Frances Hospital-Tyler.

The affidavit indicates Tyler police investigators looked at staffing and payroll records and determined that Davis was the only nurse assigned consistently to the Cardiovascular Intensive Care Unit at the date and time of each incident. They also reviewed hospital security footage pertaining to the seven incidents and observed Davis entering the room of three patients who suffered episodes within minutes of him leaving their room.

Smith County District Attorney Matt Bingham was unable to provide information about the developments that led to the new indictments. Bingham said the case has been placed under a protective order by 114th District Court Judge Christi Kennedy.  

Information under the criminal homicide chapter of the Texas Penal Code states a person commits capital murder if the person murders more than one person during the same criminal transaction or during different criminal transactions but the murders are committed pursuant to the same scheme or course of conduct.