SNELLVILLE, Ga. -- A woman is accused of gunning down her daughter-in-law, right in front of her grandchild.

Snellville police suspected Joanna Hayes all along, but it's taken months to build their case. CBS Atlanta News was the only station to ask her the tough questions about being arrested for the killing of her daughter-in-law, Heather Strube.

“Joanna, did you kill Heather Strube? Why did you wear a wig? Did you think you were going to fool police?” asked reporter Jennifer Mayerle.

Hayes remained silent while she walked out of Snellville police headquarters.

“I think she was just trying to hide her identity because it was in daylight and there were plenty of people around,” said Police Chief Roy Whitehead.

Heather Strube was gunned down in a Target parking lot on Ronald Reagan Parkway in late April. Hayes’ son, Strube's estranged husband, had just dropped off her 18-month-old son.

Surveillance video caught the suspect walking through the Target parking lot to Strube's car and then walking out of the parking lot. Police said the suspect wore a wig and a fake mustache. The size and appearance of the suspect led police straight to Joanna Hayes.

“It's an unusual case, there's no doubt about it,” said Whitehead.

Hayes sat expressionless at her first court appearance Wednesday night. She only spoke to say she will get her own attorney.

Police believe the motive for the killing is the custody battle over Strube's son. A judge was in the process of granting Strube sole custody of the boy, and taking him away from Hayes' son, when she was killed.

Hayes' son, Steven Strube, is in the Newton County jail on an unrelated parole violation.