Cook was killed while on the phone with 911. She was found dead in her Cedar Hill home in 2012.
A judge dismissed a juror just before closing arguments on Friday after the juror was overheard in an elevator discussing the trial. The juror denied it, but was dismissed anyway.
During closing arguments, prosecutors said Patrick "cruelly murdered Deanna Cook and by God's grace she managed to record it."
"We didn't have to bring you a perfect victim. We know what killed her, not PCP," they said.
Patrick's defense attorney's maintained he is innocent, bringing up the lack of DNA evidence and casting doubt on the witness who identified his voice in a 911 call.
They said Cook's 911 call is filled with reasonable doubt and that what jurors heard was not really what happened. They suggested she died in a manner similar to Whitney Houston.
"How do you drown traumatically without making a splash? You fall asleep. Didn't hear any splashing," they said.
Prosecutors called the idea that Cook hallucinated her ex-husband saying "I'm gonna kill ya" ridiculous.
Patrick could face up to life in prison. The punishment phase of the of the trial begins Tuesday morning.