Updated

An FBI investigative team arrived at a federal prison Thursday to search for evidence following a deadly shootout between a guard and federal agents who were trying to arrest him and five others indicted in a sex-for-contraband scandal.

Corrections officer Ralph Hill, an Air Force veteran, had smuggled a gun into the prison and opened fire Wednesday morning as the FBI agents and Justice Department investigators arrived, officials and his attorney said.

Hill, 43, and Justice Department special agent William "Buddy" Sentner were killed in the exchange, and a prison employee helping with the arrests was wounded.

The FBI didn't plan to release any updates on its investigation Thursday, special agent Jeff Westcott said. The FBI shooting review team arrived late Thursday morning.

The five surviving guards pleaded not guilty and were scheduled to appear in court a bail hearing Thursday afternoon. The men were indicted by a grand jury Tuesday on charges alleging that five of them had sex with female inmates in exchange for contraband such as money, alcohol or drugs and another helped in the scheme.

Attorney Tim Jansen, who represented Hill, said his client's behavior was "totally out of character."

"He had no criminal history or issues of violence in his background," Jansen said.

Officials said the guard fired with a personal weapon — guards are prohibited from bringing personal weapons into prisons but are not screened the way visitors are. Agents from the Justice Department's inspector general's office returned fire, killing the guard. It was not immediately clear who fired the shot that killed Sentner.

"These agents were out just trying to do their job, trying to do an arrest in a very controlled situation, and it just didn't come down exactly as planned," FBI agent Michael Folmar said.

Sentner, 44, of Orlando, previously worked for the Secret Service and spent a decade at the White House, working for former Presidents George H.W. Bush and Bill Clinton, his father, also named William Sentner, told the Orlando Sentinel.

"He was a kid that was always well-disciplined. He never got into trouble," Sentner told the paper. He said his son and his wife of just more than a year, Marie, had planned to have children.

The identity of the wounded prison employee was not disclosed. Folmar said the man should fully recover. He declined to discuss details until the FBI team completes its investigation.

Hill and the five other guards had been indicted on a conspiracy charge in a sex-for-contraband scheme that allegedly went on inside the prisons for two years, prosecutors said. The contraband was not specified in the indictment but could include drugs, alcohol and money.

The detention center where the agent was shot houses mostly men who are being processed before entering the prison system and is part of the Tallahassee Federal Correctional Institution. A low-security prison for female inmates is next to the detention center. Together the men's and women's units house 1,445 inmates.

Besides the sex-for-contraband allegations, the guards were accused of threatening to plant contraband in inmates' belongings or have them sent to other institutions farther from their families if they reported the illegal activity.

According to the indictment, the guards showed inmates information about themselves and inmates on the prison computer system to prove that their threats were real. It said the guards switched assignments to arrange trysts with inmates.

They were charged with conspiracy to commit bribery, witness tampering, mail fraud and interstate transportation in aid of racketeering. If convicted, they could face up to 20 years in prison.

Hill had voluntarily supplied a saliva sample after authorities began investigating in November, Jansen said.

A woman who answered the front door at Hill's home declined to comment.