The deposit of $68,000 of state money into the Rockwall district attorney's personal bank account amounts to a mistake, not a grand, criminal conspiracy, his defense attorney contends.

James Wheeler made that assertion repeatedly Thursday while cross-examining an FBI public-corruption investigator during Ray Sumrow's trial on charges of theft and abuse of official capacity.

Prosecutors accuse Mr. Sumrow, 58, of intentionally diverting three deposits meant for his office into his personal checking account. They say he used the money for personal expenses before repaying the last of it about one year after the first deposit.

Mr. Sumrow has denied wrongdoing. He admits signing a deposit authorization form that triggered the deposits but says he thought it related to his paycheck, which also comes from the state.

"Doesn't it appear that this could be a simple human error?" Mr. Wheeler asked FBI Special Agent Brent Chambers.

"No, sir. Not with me knowing all the facts of the case," Agent Chambers replied. "His statements vs. the facts of the case – that's where I have the concerns."

Mr. Sumrow has repeatedly changed his explanation, telling one story to investigators and another to a Travis County grand jury investigating the case, Agent Chambers said.

"But you don't know if it was a mistake," Mr. Wheeler said.

"I have my feelings," Agent Chambers said. "I'll defer to the jury to decide that."

Mr. Wheeler insists that law officers have inflated a long-settled bookkeeping error into a criminal conspiracy. Mr. Sumrow testified before a grand jury and in another court case that he told county commissioners about the situation and they had no concerns.

"The commissioners knew about it. People in my office knew about it," he said in March. "It wasn't any big secret."

But commissioners Bruce Beaty, David Magness and Jerry Wimpee testified that they first learned about the misdirected funds when the media reported in spring 2007 about the criminal investigation of Mr. Sumrow.

Sheriff Harold Eavenson asked the FBI and Texas Rangers to investigate Mr. Sumrow beginning in fall 2006. Former county Treasurer Shereé Jones told them about Mr. Sumrow's actions after she admitted taking and later repaying $2,100 in county money.

Days after Mr. Sumrow learned about the investigation, a software program called Evidence Eliminator was used to permanently remove more than 18,000 files from his computer, said Rod Gregg, an FBI senior forensic examiner.

Mr. Gregg said he could not recover the destroyed files or determine their nature. Prosecutors call the program's use suspicious.

This is the second trial for Mr. Sumrow, who served as Rockwall district attorney for 20 years.

In March, a separate jury convicted him of theft by a public servant for stealing computer equipment and money from another office account. He was sentenced to four years' imprisonment in that case but is free on bond pending an appeal.

The Republican, first elected in 1986, was removed from office after that conviction. He could face as many as 20 additional years in prison if convicted in the current case.