A 10-year-old boy died after his pet rat bit him his family claims. Now their suing Petco, the store where they bought the rodent. The attorney handling the case argues Aidan was bit by the rat and then died from rat-bite fever. The defense says the boy's grandmother, who purchased the pet, signed a document with a health warning on it. Whether Petco sold an infected pet and whether the company could have prevented Aidan's death will be the focus of the trial that's now underway.