Delaware prosecutors are dismissing all but three remaining cases against inmate defendants charged in a deadly prison riot.

Friday's decision comes after earlier trials of seven inmates resulted in only one convicted of murder in guard Steven Floyd's death.

With little physical evidence, prosecutors have relied heavily on testimony from other inmates who were in the building at Delaware's maximum-security prison during the 2017 riot but were not among the 18 charged.

Defense attorneys have argued that the prosecution witnesses have contradicted one another and that their testimony conflicts with statements they gave investigators.

Floyd was killed and two other guards beaten and later released before tactical teams stormed the building and rescued a female counselor.