A bank teller allowed a south Texas mayor to deposit a $26,000 check made out to someone else into his business account, the clerk testified Tuesday at the politician's theft trial, because he did not think the well-known figure would be breaking the law.

Prosecutors say Brownsville Mayor Pat Ahumada deposited the check into an account for his real estate appraisal business and spent more than $5,000 over the following three weeks.

During that time, prosecutor Luis Saenz told jurors, "nobody knows anything except the defendant," and then when it was revealed, "Ahumada engages in a campaign to discredit the investigation."

Ahumada initially said he did not remember depositing the check. When the bank notified him later he asked the official to investigate because he believed political enemies could be setting him up.

It was "an innocent mistake" by a busy mayor on his way to Mexico on city business, his attorney Ed Cyganiewicz said Tuesday.

"He's not stupid enough to deposit a check that doesn't belong to him," Cyganiewicz told jurors.

Ahumada pulled into a commercial business lane at his local bank branch to make a deposit on Oct. 28. He endorsed the back of a $26,139 check from the city of Brownsville to Tarsia Technical Industries of New York for equipment at the public library and added his account number.

Teller Julio Salazar testified that he noticed that the check was not made out to the mayor, but he accepted it and filled out a deposit slip because he knew Ahumada and "I never thought he would be breaking the law by giving me this check." Salazar said he was put on probation for three months for violating bank policy.

Tuesday's testimony illustrated that as mayor, Ahumada could not only deposit a large check made out to someone else unchallenged, but also call the head of the Brownsville-South Padre Island International Airport that same morning and ask him for a ride to the airport. Ahumada told airport chief Larry Brown only once they were on their way that the airport in Matamoros, Mexico, was actually where he needed to go, Brown said.

Brown testified that when he arrived at Ahumada's house that morning, the mayor said he had to run an errand first -- maybe to the bank, Brown could not recall. After Ahumada returned, they left for the airport in Brown's city truck. Ahumada was flying to Mexico City for a meeting about a river project.

Tarsia Technical Industries later contacted the city to find out why it had not been paid, and the city traced the check.

Hugh Emerson, a vice president at BBVA Compass Bank in Brownsville, called Ahumada on Nov. 21 to let him know that the security department would be withdrawing the money that was improperly deposited in his account. Ahumada came in that day to make a deposit so that there was enough money in the account, Emerson testified.

"He was very concerned that this check had been deposited to his account," Emerson said.

What remains unclear is how the check ever made it from the city's finance department to Ahumada, who is serving the second year of a four-year term as mayor of Brownsville.

Three employees of the city's finance department, which issued the check for Tarsia Technical Industries, testified that they had no idea how it got to Ahumada. There was an $81 travel reimbursement check issued for Ahumada the same day, but the city manager's executive assistant said she did not recall picking it up for him.

The city of more than 170,000 is about 275 miles south of San Antonio.

In a voluntary statement that Ahumada gave to police in December, he said he suspected someone with malicious intent was trying to get him or he had made a mistake. He mentioned a private investigator that had been paid $5,000 to follow him and a mysterious vehicle that sometimes tailed him trying to catch him driving drunk.

Testimony was scheduled to resume Wednesday.