A third prison guard charged in a sex-for-contraband scandal that ended in a deadly shootout between a corrections officer and federal agents pleaded guilty to mail fraud.

E. Lavon Spence told a federal court Tuesday: "I had sexual contact with inmates and brought in contraband." He said that contraband included cigarettes.

In exchange for his guilty plea, the government dropped other charges including witness tampering, bribery and intimidation of witnesses.

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Spence could face up to 20 years in prison, a $250,000 fine and three years of supervised released. Sentencing was scheduled for December.

He was arrested June 21 along with four other guards at the Tallahassee Federal Correctional Institution. A sixth officer, Ralph Hill, was killed in a shootout after he opened fire on federal agents. Justice Department special agent William "Buddy" Sentner was also killed.

The six were accused of a scheme in which guards paid female inmates for sex with alcohol, food, money and marijuana over a two-year period, and intimidated inmates and witnesses to ensure their silence.

Two of the guards, Alfred Barnes and Vincent Johnson, pleaded guilty to mail fraud in September. Two others, Gregory Dixon and Alan Moore, are scheduled to go to trial Oct. 30. Dixon's attorney filed a motion Friday to dismiss an indictment against him.