DURHAM, N.C. — Jurors heard from a blood spatter expert Wednesday in the Mike Peterson trial, but a key point in the trial will take place Monday. On Monday morning, testimony will continue in the trial, but later in the afternoon, Judge Orlando Hudson will consider whether a 1985 death is relevant to the trial.

Even though Elizabeth Ratliff died nearly two decades ago, District Attorney Jim Hardin calls her death critical to his case against Mike Peterson.

Ratliff was a friend of Mike Peterson who died in 1985 in Germany. Like Kathleen Peterson, her body was found at the bottom of a staircase. The prosecution had Ratliff's body exhumed in Texas, and a new autopsy concluded she was murdered. The medical examiner found several deep cuts to the back of her head, similiar to the ones found on Kathleen Peterson.

In the next few days, seven witnesses will fly in from around the country and as far away as Germany. Hardin will call on them to show why he thinks Ratliff's death should be admitted as evidence.

Among the witnesses set to testify next week are Elizabeth Ratliff's sisters, a woman who worked for Ratliff, and some neighbors who lived near Ratliff and Peterson in Germany. The hearing will take place outside of the jury's presence.

One key witness who will not be in Durham is Karin Hamm, Ratliff's neighbor. Hamm has told police she saw Mike Peterson quickly leaving Ratliff's house the night of her death. A medical condition prevents her from flying, so prosecutors hope to enter her statement through a deposition.

Peterson has maintained all along that Ratliff died of natural causes as stated in the original autopsy.

Kathleen Peterson's blood was the main topic Wednesday as prosecutors put the state's blood spatter expert on the stand.

Peter Duane Deaver, a 16-year veteran with the State Bureau of Investigation, showed jurors more pictures of the bloody stairwell where Kathleen Peterson's body was found. Mike Peterson is charged with the death of his wife.

Deaver also showed jurors charts and diagrams that pinpoint where blood was found on the walls and steps and interpret those blood-stain patterns.

Defense attorney David Rudolf argued Deaver is not qualifed to testify as an expert.

"You have not written any articles for any professional journals?" Rudolf asked.

"No, I have not," Deaver said.

Deaver is expected to be on the stand for several days.

Earlier in the day, jurors looked at personal papers found in Mike Peterson's desk the night of Kathleen Peterson's death, including a naked picture of Brent Wolgamott, a former male escort who Peterson allegedly tried to hire for sex.