An Allegheny County judge yesterday ruled that a Braddock father accused of sexually assaulting and killing his toddler daughter will not be tried simultaneously for a separate sexual assault.

Common Pleas Judge David R. Cashman reversed his own ruling from last year, when he joined the two cases against 25-year-old William Lorenzo Page.

In addition to the sexual assault and murder of 23-month-old Nyia Page -- who was found half-naked and frozen in a wooded area in Rankin -- Mr. Page is charged with sexually assaulting a 6-year-old boy in his home. Prosecutors claim the assault occurred Feb. 2, 2007, the day before Mr. Page left his daughter to die. Prosecutors are seeking the death penalty against Mr. Page.

"This is the total picture," Deputy District Attorney Mark V. Tranquilli argued in trying to keep the two cases together. "This is a night in the life of William Page, and this is what he did with it."

Defense attorneys Christopher Patarini, of the public defender's office, and J. Richard Narvin, of the Office of Conflict Counsel, argued that the assault wasn't directly related to the killing and was meant only to garner additional ill will against Mr. Page from the jury.

"The death of a child strikes such a chord with jurors, this will be unduly prejudicial," Mr. Narvin said.

Also yesterday, Judge Cashman denied a motion to throw out Mr. Page's confession, allowing his statement to police about the killing to be presented at trial.

And Mr. Tranquilli withdrew a charge of aggravated assault against Mr. Page for kicking Nyia in the groin. Mr. Page told police he did so, but there was no physical evidence of a kick.

Jury selection for the trial is scheduled to begin Oct. 13.