The commander of criminal investigations for the Carroll County Sheriff's Office was charged with misconduct in office Wednesday and resigned, following an investigation that led county prosecutors to drop charges in two high-profile killings.

The Office of the State Prosecutor, which investigates public corruption and other crimes, alleged Wednesday that Maj. Nicholas Plazio made false statements to prosecutors and in court in connection with the fatal 2010 stabbing of 25-year-old Jeremiah P. DeMario. Plazio is accused of lying about his role in the illegal interviews of two suspects in that case.

"Any law enforcement officer, let alone a commander of a criminal investigations unit, must be held to the highest standards of conduct and integrity," said State Prosecutor Emmet C. Davitt. "False reports and false testimony are never acceptable under any circumstances and cannot be tolerated."

The state prosecutor's office had also been investigating Detective Douglas Epperson in connection with the DeMario case, but Davitt would not comment on that part of the probe. Epperson has not been charged, and his attorney said he has done nothing wrong.

The state prosecutor's investigation led the Carroll County state's attorney's office in March 2012 to drop charges related to the death of Isaiah Simmons III, a 17-year-old resident at Bowling Brook Academy. Epperson had been the lead detective on that case.

State's Attorney Jerry F. Barnes said at the time that the state prosecutor's investigation was a major reason for his decision. Simmons died in 2007 after he was restrained by staff members at the juvenile detention facility.

In the DeMario case, Russell S. Laderer Jr. faced murder charges and Cassandra L. Glover was accused of being an accessory after the fact. Prosecutors dropped those cases in March 2012 after a Carroll County judge made a series of rulings that much of the evidence against the suspects could not be used because it was illegally obtained.

Davitt said Plazio's alleged false statements damaged the case. He referred further questions to Barnes, who declined to comment.

In a March court filing announcing that he was dropping the charges against Laderer and Glover, Barnes blamed "damaging law enforcement conduct" that was "avoidable and inexcusable" for the collapse of the cases.

The charging document in Plazio's case alleges that he lied when he said he did not watch the interviews of Glover and Laderer, and when he said that he did not tell Epperson to go back into an interview room after Glover had asked for a lawyer.

The judge handling the cases ruled that those interviews had been conducted after Glover and Laderer were unconstitutionally arrested and that information obtained during them could not be used in court.

Spokesman Maj. Phillip S. Kasten said the Carroll County Sheriff's Office is cooperating "fully" with the state prosecutor's investigation.

"Until the results of this independent investigation are known, any further comments would be inappropriate and speculative," he added.

DeMario's father, Richard DeMario, 52, said he thought someone "truly got away with murder" because of the way the sheriff's office handled the case.

"There is some comfort in knowing that Major Plazio will be placed on trial for misconduct," he said, adding that his family will be following the case closely.

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