The news hit the Arlington Police Department like a ton of bricks: On Tuesday afternoon, a three-year veteran named Danial Vo shot and killed himself in the woods near his home on Tuesday. Some time earlier a fellow officer, Thomas Kantzos, had been arrested by the FBI. Both were the target of a criminal probe involving some type of computer-related fraud, Arlington PD announced, but it declined to give more details.

A federal criminal complaint filed against Kantzos today provides a much clearer picture of the allegations. According to court documents, Kantzos used his access to state and federal law enforcement databases to illegally run at least a half-dozen names and license plates for a suspected drug dealer. The first time this happened, in December 2011, the dealer discovered that the man with the laptop parked down the street was a member of a local drug task force and that someone had hidden a tracking device on his car.

But that just scratches the surface of Arlington PD's troubles. The drug dealer was arrested in January 2013 and became a cooperating witness. He told the FBI that Kantzos had been a customer for at least five years, regularly stocking up on steroids and human growth hormone. Once, he told agents, he had even delivered a shipment to Kantzos while the cop was in his squad car, in uniform and on duty.

But Kantzos wasn't the only one. Text messages (""oy from work wants a test and a dec....") and phone conversations revealed that a whole mess of Arlington cops were doing steroids. The dealer -- he's identified in court documents only as "CW," or cooperating witness -- had supplied several. At least two of the license plates checks were conducted by Kantzos' Arlington PD colleagues when he wasn't at work.

Following the his arrest, FBI agents built a criminal case by recording the dealer's texts and phone calls. During one conversation in April, Kantzos seemed concerned by the arrest of a couple of dealers who'd been selling steroids to his colleagues. He wanted to know if the dealer was connected at all to the arrestees and whether it would affect his supply.

"All our sources dried up," Kantzos explained, going on to promise that "You'll be back in business" and "I got like five guys that are fucking 'jonesin.'"

That was in April. The court documents don't say why the FBI waited to arrest him, nor do they name Vo, but then again, it wouldn't have any reason to. He's dead. Kantzos, meanwhile, was taken to Tarrant County Jail where he faces a charge of exceeding authorized access to a protected computer, which carries a maximum 10 years in prison and $250,000 fine.