Daryl K. Washington, one of the family attorneys for the Jean family, spoke out against the sergeant who took the stand during the trial of Amber Guyger in her defense.

Washington visited on SiriusXM Urban View's The Clay Cane Show to express his disbelief at Sgt. David Armstrong's testimony:

"David Armstrong was exhibit one to officers who should never have the opportunity to investigate another officer."

He continued, "The same individual, by the way, who signed the arrest affidavit. He wanted to get up so badly and tell this jury that he didn't think that she did nothing wrong. Basically, he bought her entire story. He had basically made his decision after his first day being on the scene, that she did nothing wrong without conducting a proper and adequate investigation. Not once did they do anything to even test the sofa to confirm that there was any type of blood on the sofa to see if Botham was actually sitting on the sofa."

Washington slammed the Texas Ranger's handling of the investigation:

 "There was so much that the Texas Rangers did in this investigation that was not right. In other words, they came in to try to help her. They didn't not come in to try to do a complete, thorough, and accurate investigation."

This week, a Dallas County jury found Guyger, 31, guilty of murder, choosing the more severe conviction over a lesser option of manslaughter. She was later sentenced to 10 years in prison and is required to serve at least five years before she is eligible for parole.

Listen to the full interview below: