Is circumstantial evidence enough to convict?

This is a very interesting case because all the evidence the Prosecution has to convict this woman is circumstantial. I have followed most of the case and have watched the courtroom footage. All of the circumstantial evidence against her is very strong. William was shot prior to being dismembered. His wife, Melanie, purchased a gun only days before his disappearance. Also, the bullets that killed him were the same type of bullets she purchased with the handgun. The suitcases he was found in matched the luggage set owned by the McGuire’s. The blanket that William’s head was wrapped in that was found in one of the suitcases is made by the same company that provides blankets to the hospital where she worked. Then there was the family computer that was confiscated when she was arrested. The computer contained Google searches for such things as undetectable poison and murder and suicide.