Robby Gordon's stepmother appears to have been murdered. She was found strangled, while his father apparently shot himself. This is an apparent murder suicide, which is how the police are investigating the matter. It seems the most plausible explanation, wnd there has been no mention of forced entry or a possible robbery.
The evidence found at the scene of the crime supports the notion of a murder. Her husband was found with a self-inflicted gunshot would meaning he would have had to take his wife's life first. A knife lay at the crime scene but reports say she was also strangled. More on this investigation is pending, but from how the news has described the situation, it seems probable that his step mother was murdered.
I believe that Robert Gordon Sr. strangled his wife and then shot himself. The couple were probably engaged in a heated argument that turned violent, as evidenced by the butcher knife found near Sharon Gordon's body. When Robert strangled his wife, either in a rage or in self-defense, he became distraught and then took his own life.
Yes, Robby Gordon's step mother was murdered because police found her strangled to death. Her husband also died, but that may have been due to suicide. It appears that the husband killed his wife and then turned the gun on himself. It is a tragedy for the Gordon family who survives them.