The jury considering the fate of Mehmet Hakan Atilla, a Turkish banker charged with participating in an oil-for-gold smuggling scheme that violated United States sanctions against Iran, was sent home by the judge on Wednesday after deliberating for half a day without reaching a verdict.

Mr. Atilla, 47, was a deputy general manager of a Turkish state bank, Halkbank, that prosecutors say was crucial to the success of the sanctions evasion. The government presented evidence that Mr. Atilla helped to devise the scheme and that he deceived United States Treasury Department officials about it.

“This is a case about lies,” a prosecutor, Michael D. Lockard, said Tuesday in the government’s closing argument. “This is a case about the lies that Mr. Atilla told to cover up a multibillion dollar sanctions-busting scheme operating out of his bank.”

Mr. Atilla, testifying in his own behalf, denied that he had participated in any such conspiracy or that he had engaged in wrongdoing. His lawyers painted him as the victim of Reza Zarrab, a Turkish-Iranian gold trader who pleaded guilty in October and has been cooperating with the government.