Defense attorney Jimmie Berry says his client, a former Polk County police detective accused of operating a chop shop, is not the dirty cop he has been made out to be by the prosecution but is instead a victim and a “marked target.” But a federal prosecutor claims that evidence found on the defendant’s own property is overwhelming.

Mark Howell Sparks, 40, maintained his innocence as his trial began Thursday in U.S. District Court in Rome.

In March, Sparks was indicted on six criminal charges including running an illegal chop shop, tampering with vehicle identification numbers and interfering with a federal investigation by allegedly tipping off the targets of the investigation.

The defendant was one of six men arrested in October in connection with a car theft ring in Polk County. According to Assistant U.S. Attorney William McKinnon, the men were stealing vehicles, finding similar vehicles that had already been totaled and replacing the vehicle identification numbers of the stolen vehicles with those from the totaled cars.

McKinnon said the most damaging evidence was vehicle parts such as truck cabs and frames found in a Cedartown warehouse rented by Sparks.

“Mr. Sparks undoubtedly possessed these vehicles for a number of years,” McKinnon said.

McKinnon said the prosecution will prove that Sparks knowingly drove a stolen vehicle with mislabeled VIN and that Sparks had a close relationship with the others arrested in the alleged ring.

Defense attorney Jimmie Berry maintains the men actually running the chop shop set up his client as a “marked target” and that his client was aware of the ongoing investigation but distanced himself due to his close relationship with the men being investigated.

Berry also stated that Sparks no longer possessed a key to the rented warehouse where chopped vehicles were recovered and had not been there in years.

The defense argues that many of the witnesses for the prosecution gave changing testimonies, including informant Robert Cates, a conspirator in the alleged theft ring.

“You will find that Robert Cates gave a lot of differing statements,” Berry told the jury.

Sparks’ trial will continue today at 9:30 a.m. in Judge Harold L. Murphy’s courtroom.