The expert testimony is expected to wrap up this afternoon.
Prosecutors and defense attorneys could present their closing arguments this afternoon.
Wyngarden faces two charges of first degree premeditated murder for the 1987 deaths of Gail and Rick Brink in their Ransom Street home and will serve life in prison if convicted.
The prosecution says Wyngarden killed Gail and her husband Rick Brink out of jealously and to cover up an incestuous relationship when the siblings were teens.
Wyngarden’s defense has said the couple could have been killed in a case of mistaken identity because the previous owner of the Brink house dealt drugs brought from Detroit.
This morning, Ryan Wyngarden finished three days on the witness stand marked by rambling stories, objections from attorneys and comments from Judge Jon Hulsing about “antics” in front of the jury.
Prosecuting attorney Lee Fisher continued quoting letters Wyngarden sent from the Ottawa County Jail to his wife Pam, who has said her husband confessed to the murders. Fisher said the letters and phone calls were designed to influence Pam through Bible quotes, prayers, threats of lawsuits and intimate details.
Wyngarden included explicit descriptions of love making to try to entice his wife to change her mind, Fisher said.
“I put something in about being good in bed,” Wyngarden said, saying he was “dynamite” with sex.
“You were trying to get her to change her testimony, weren’t you?” Fisher asked.
Wyngarden said he was often emotional when he wrote the letters to his wife, family and friends.
When questioned by his defense attorney David Hall, Wyngarden denied earlier police interviews that the sexual relationship with his sister resulted in penetration.
When asked if he killed Gail and Rick Brink, Wyngarden said no.
The jury asked the judge about 15 questions regarding Wyngarden’s testimony, from where he spent the night after the murders and why he canceled an appointment with a friend in Muskegon to if he thought about killing Gail and Rick Brink. That’s the highest number of questions asked of the more than 50 witnesses in the case that started March 11.
— By Jim Hayden, The Holland Sentinel