The death of former New England Patriots tight end Aaron Hernandez was ruled a suicide, the Worcester County District Attorney’s Office announced on Thursday.

Hernandez was found hanged by a bed sheet inside his cell at the Souza Baranowski Correctional Center in Shirley, Mass., early Wednesday morning and was pronounced dead the hospital about an hour later.

The Massachusetts chief medical examiner, Dr. Henry N. Nields, concluded the “manner of death was suicide and the cause asphyxia by hanging,” according a news release.

“There were no signs of a struggle, and investigators determined that Mr. Hernandez was alone at the time of the hanging,” the district attorney’s office said in the statement.