Nina Parton didn’t know why a couple guys would kill her father on his daily mail route.

Bruce Parton had been doing the same route for 10 years, and knew everyone in the Miami suburb. Then, in December 2010, he was shot twice and died on the spot. Only when the police arrested the murderers four months later did Nina Parton learn that the attack was part of a plot. The two young guys had been cruising the neighborhood looking for a mailman, hoping to steal a mailbox master key, and then use the residents’ identities to file tax returns in their names.

“It would be less expensive for them that way,” Nina Parton told America Tonight. “My dad was 60 years old and something like 5-foot-5,” she added — easy prey.

Identity theft is America’s fastest-growing crime, and tax-return fraud has become one of its most dynamic subsets. Criminals are leaving street corners for living rooms, and trading drugs for laptops, lured by the promise of more money for less hustle. According to the IRS, indictments and sentencing for tax-return fraud doubled last year, and the agency has described identity theft as the number one tax scam of 2014.

Prospective tax thieves need just three things: your name, Social Security number and birth date. (Those personal records are cheaply available on the black market.) They can then electronically file thousands of false tax returns with made-up numbers for your income and deductions. Within a couple of weeks, your refund is in the swindler’s pocket -- possibly spent on cars and other luxury items, before you even file your taxes.

The IRS does not have third-party information to effectively verify your income when tax returns are processed. So when a thief gets a fraudulent refund, the burden is on the victims to prove to the IRS that they are the legitimate taxpayers.

To collect the stolen tax returns, thieves often use prepaid debit cards, which can be bought in regular corner stores, require no bank account and allow money to be laundered quickly and easily. That way, they don’t have to bother with banks or check-cashing stores that may become suspicious when one person brings in several tax-refund checks. Several detectives have reported pulling over drivers and finding stacks of prepaid cards, along with stolen identity data.