The trial has become one of the longest not involving the death penalty in Raleigh history.
The conclusion of the defense's case came after testimony Thursday from a witness who said he could not see a diamond necklace in surveillance video of Nancy Cooper from a grocery store on July 11, 2008. That's the day before she went missing.
The necklace has been a key point in the murder trial. Brad Cooper is accused of killing his wife Nancy. She was last seen alive by friends at a neighborhood party in her Cary subdivision the evening of July 11.
Cooper told detectives his wife returned late that night and went out for a run around 7 a.m. the next morning, but never returned. Her body was found by a drainage pond in an unfinished subdivision a few miles from her home two days later. The medical examiner said she had been strangled.
Nancy's friends and family have testified that she never took off her diamond necklace. It was not found on her body. Instead, it turned up in a drawer in a room that Brad Cooper's mother was using after Nancy's death.
Witnesses also said Nancy jogged with her keys, which were also found in the Cooper home.
On the witness stand Wednesday, private investigator Richard McGough played the surveillance video of Nancy and said it did not appear that she was wearing the necklace just hours before she was last seen alive.
Prosecutors rested their case last week. They allege Brad killed Nancy because he was angry she planned to divorce him and move with their two daughters to Canada.
Cooper's lawyers say he is innocent and have characterized the investigation by the Cary Police Department as inept. They say detectives focused on Cooper from the beginning of their investigation and never looked at other suspects.