According to a complaint released Wednesday by the U.S. Department of Justice, 45-year-old Arlington police officer Thomas S. Kantzos was arrested Tuesday night and has been charged with tipping off a known drug dealer to a police investigation.
In a sworn statement, an FBI agent said a man who was arrested in January for distributing anabolic steroids and human growth hormones agreed to cooperate in the investigation.
The man, identified only as a cooperating witness, admitted that over the last several years he provided steroids and HGH to Kantzos.
On at least one occasion, the witness delivered about 20 hits of HGH to Kantzos, a 17-year veteran of the Arlington Police Department, while Kantzos was on duty, in uniform and in a marked Arlington police car, the complaint alleges.
The affidavit outlines a lengthy relationship between Kantzos and the witness in which the officer would regularly text the supplier about the availability and cost of drugs to be used by himself and others within the department.
The agent said that text messages he reviewed from Kantzos indicated he seemed "familiar with the types, dosages, uses and prices of various forms of anabolic steroids." Kantzos sought steroids for himself and others, "including friends and colleagues in the Arlington Police Department."
The complaint also alleges that Kantzos put the witness in contact with at least two other officers so that they could obtain steroids directly from the witness.
According to the court document, the FBI secretly recorded a meeting between the officer and the supplier on April 12.
"Remember about two years ago I had a guy who bought 20 bottles from you?" Kantzos asked the man, according to the document. The officer later added: "You'll be back in business ... I got like five guys that are (expletive) 'jonesin.'"
The witness told investigators that he was concerned police were watching him. On several occasions, he asked Kantzos to use police computers to look up license plate numbers and other personal, sensitive information, he said. The witness said Kantzos obliged and the information led to the witness finding in December 2011 a tracking device that had been installed on his vehicle.
"Kantzos was authorized to access law enforcement information obtained through the Texas Crime Information Center (TCIC) and the National Crime Information Center (NCIC), and he received specialized training on the authorized uses of the information, as well as the potential penalties for the misuse of such information. Personal use of such information, including releasing information to members of the general public, is not authorized and violates APD policy," the Justice Department said in a news release Wednesday.
After the tracking device was found, the witness said he began "laying low," while still talking with Kantzos about the tracking device and surveillance against him.
Kantzos was held overnight in the Tarrant County Jail and appeared in federal court in Dallas on Wednesday afternoon.
A federal magistrate released him under a number of conditions, including that he turn in his passport, surrender his police credentials and stay off illegal drugs.
Kantzos is charged with exceeding authorized access to a protected computer. If convicted, he could spend 10 years in a federal prison and face a $250,000 fine, per count.
Two other Arlington officers, 35-year-old David Vo and 34-year-old Craig Hermans, have been under investigation by the FBI and the Texas Rangers.
Vo committed suicide Tuesday near his home on the 2400 block of Park Run Drive. Vo, a three-year employee with the department, had been arrested and released over the weekend and was on administrative leave.
Hermans, who has also been with the department for three years, is also on administrative leave pending the outcome of the investigation.
NBC 5's Scott Gordon contributed to this report.