>> reporter: brian witham gave them the answer. they'd bought masks. so agents, who is this?he zeigler robbery in april of 2015. >> reporter: the one who said, "the baby needs some milk"? >> yes. >> reporter: remember the fbi had released a sketch of her to the public. it was eerily close. so what's actually happened here? >> brian witham had a fake tattoo on his neck walked outside, put that mask on, and then came in and acted like a female coming in. looking for milk for the baby. >> reporter: as for the african-american man, he was a mask as well. benanti's dna was found on it. pretty good masks. >> yeah. >> ye -- yes. they spent roughly $1,500 a piece we later found out to purchase these masks. >> they were sewing in deception and red herrings and things designed to confused the victims. >> reporter: the gender switch, the racial switch. >> yeah, all of that. because the victims then are going to report all of that to the police. and the police will then be looking for a black man, a woman with long brown hair. >> reporter: and it worked. witham also told the agents that