Detective: Lowe's receipt contradicted Brad Cooper

Detective Jim Young said investigators found a receipt in Brad Cooper's car from a Cary Lowe's home improvement store for an 8- by 12-foot plastic drop cloth. A surveillance video shows the purchase was made at 9:30 a.m. on July 11, 2008, the day before Nancy Cooper's death.

Full video: Day 13 trial testimony

That was about the same time, Young said, that Brad Cooper told him he was running late for work because he had been at home helping his wife with their two young daughters.

Five days later, investigators found what appeared to be an unopened drop cloth in a Home Depot bag beneath a workbench in Brad Cooper's garage.

By that time, Nancy Cooper, 34, had been reported missing when she failed to return home from a morning jog, and her body had found in an undeveloped subdivision several miles from her home.

Brad Cooper, 37, was arrested more than three months later and is standing trial for first-degree murder.

Defense attorneys have said in opening statements that their client bought the drop cloth for his wife who had been painting at a friend's house, but it had never been used.

Young also testified Monday that cell phone records showed Nancy Cooper tried several times on July 11 to call her husband at work and that those calls were forwarded to his cell phone. One call went to voicemail, while two others went unanswered.

It wasn't until 2:32 p.m. that day that she was able to connect with Brad Cooper, Young said.

Brad Cooper's cell phone records also showed data usage at 6:25 a.m. on July 12, 2008. At 6:25 a.m., Young said, Brad Cooper was also in a Harris Teeter, several miles from his home, buying milk.

At one point in surveillance video, Young said, it appears that Brad Cooper is interacting with his cell phone before paying for the milk and again before he picks it up to leave the store.

Defense attorneys have said Brad Cooper went to the store to buy milk for the younger of the two Cooper children.

When he got home, they have said, his wife asked him to go back for laundry detergent, and while he was on his way, she called him to also pick up some juice.

Young said that Brad Cooper was wearing a pair of sneakers on the first trip that have never been recovered and a pair of open-toed shoes on the second trip.

He also noted that on the first trip, Brad Cooper "makes a motion as if he's wiping sweat from his brow" as he enters the store and then rubs his hand on the rear right side of his blue jeans.

Prosecutors have said that Brad Cooper killed his wife sometime during the early-morning hours of July 12, 2008, and transported her body to a drainage ditch outside Cary's town limit, about 3 miles from their home.

His attorneys, however, have said that their client didn't kill his wife and that Cary police ignored evidence that didn't support their "Brad-did-it theory."

One claim they have made is that Young wiped Nancy Cooper's AT&T password-protected cell phone of data that could have helped find her killer.

Young testified Monday that an AT&T representative told him on Aug. 9, 2008, that he would be prompted for a special code he had been provided after entering an incorrect password several times but that it erased the phone instead.