DURHAM, N.C. — A blood spatter expert says Kathleen Peterson's death was no accident and Judge Orlando Hudson ruled Friday that the jury will get to hear that opinion, despite objections from the defense.

In a special hearing outside of the jury's presence, SBI agent Peter Duane Deaver believes Kathleen Peterson was beaten to death in the stairwell. Mike Peterson, Kathleen's husband, is charged with her death.

Defense attorney David Rudolf interviewed Deaver for four hours. He questioned Deaver's every step in his bloodstain analysis

of the Peterson mansion. Rudolf said the experiments conducted on the bloodstains had no scientific validity.

"Can you tell me how many different events created the spatter on the north wall?" Rudolf asked.

"Not completely," Deaver answered.

Deaver said the size, shape and placement of the blood on the stairwell suggest Kathleen Peterson's head was slammed against some of the molding and that she was beaten with an object. Prosecutors believe Mike Peterson may have used a fireplace poker to kill his wife.

Deaver also said his analysis places Mike Peterson at the scene. He said the blood spatter found inside Mike Peterson's shorts that were worn on the night of his wife's death suggests force was used.

Deaver will take the stand Monday and testify in front of the jury.

Next week, Hudson is also expected to rule on the admissability of evidence regarding Elizabeth Ratliff. Ratliff was a friend of Mike Peterson, who died in 1985 in Germany. Like Kathleen Peterson, Ratliff was found dead at the bottom of the stairs with deep gashes to the back of her head.

In a hearing outside the jury's presence Monday, District Attorney Jim Hardin will explain why Ratliff's death is relevant to this case. The prosecution believes the information is so critical to their case, they are flying in seven witnesses from around the United States and Germany to testify.

In addition, the state medical examiner is expected to explain next week why the seven cuts to the back of Kathleen Peterson's head prove she was murdered. At that point, prosecutors plan to wrap up their case and turn things over to the defense.