Click here to read the affidavit.
The affidavit came up in court Wednesday as part of the custody battle over the Cooper children.
Only attorneys and Nancy Cooper's father, Garry Rentz, attended the hearing.
Brad did not attend, but his attorneys told the judge about the witness, Rosemary Zednick, who says "at approximately 7:10 a.m., I saw Nancy Cooper running on Lochmere Drive…"
Zednick lives less than a mile from the Cooper home in Cary's Lochmere Subdivision.
She says she came face to face with Cooper while she was walking her dog.
"I am positive that the woman I saw was Nancy Cooper," Zednick says in her affidavit.
But Zednick also says that while Cary police were searching Brad's home and office in RTP, they ignored her tip.
"I left my statement with the police. To date, no officer has come to speak with me," she said.
That was part of the argument Wednesday by Brad's attorneys who want Cary Police to release to them all evidence in the murder case.
But the judge hearing the custody battle over the Cooper children said that request wasn't appropriate for the civil case.
She suggested that instead they simply ask questions of the Cary detective heading up the case when he takes the stand in the temporary custody hearing Thursday.
"It's almost impossible to really cross examine someone without the information that they have," Brad Cooper's attorney Howard Kurtz said.
Although Brad has never been named as a suspect in the murder of his wife, Nancy Cooper's parents have emergency custody of Brad and Nancy's two young daughters.
"We'll be really pleased with whatever comes out of tomorrow," Rentz said. "It's the court's decision we're looking for and will respect that decision when it's made."
Thursday the judge will decide whether they get temporary custody. But when it comes to full custody, the next step, the judge will have to decide Brad's parental rights and she's already said that may mean she will have to determine whether he killed his wife.
Town of Cary Police Chief Pat Bazemore released a statement in reference to the criminal case Wednesday.
"Once again I'll remind everyone that the civil custody matter and our investigation into Nancy's murder are two separate issues, and we won't be commenting on or sharing the details of that investigation unless compelled to by the courts," Bazemore said. "Of course we continue to strongly encourage anyone with any information into Nancy's death to contact the Town of Cary Police Department right away."