Cooper, 37, faces two counts of intentional homicide in the death of 21-year-old Alisha Bromfield, also of Plainfield, and her unborn daughter.
It's the second time he will be tried in the case. Last June, a jury could not reach a decision on the homicide charges, but found Cooper guilty of third-degree sexual assault.
Prosecutors allege that Cooper, who was not the baby's father, flew into a rage after Bromfield refused to rekindle a romantic relationship. He is accused of strangling her, then sexually assaulting her body.
Cooper and Bromfield were in Door County for the wedding of Cooper's sister, Kelly Stryker.
Stryker has stood with Bromfield's family, testifying before Wisconsin legislators against a state statute that allowed her brother to use his alleged drunkenness as a defense. Cooper claimed he was too drunk to form intent when he killed Bromfield.
Last month, Stryker called last year's mistrial the "ultimate injustice," saying her brother "cold-heartedly murdered Alisha and her unborn daughter, Ava Bromfield."
Judge D. Todd Ehlers denied a continuance motion on Wednesday; the retrial is scheduled to begin next month, with jury selection on May 2, according to the Door County Advocate.
Ehlers' decision came a day after the Wisconsin Senate passed a bill that would strike down the so-called "drunk defense" statute. The bill will head to Gov. Scott Walker.
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- Murder Charges Filed in Door County Slaying of Pregnant Woman
- Plainfield Man on Door County Murder: 'There's No Good Reason'
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