(CNN) -- In his last days in office, outgoing Mississippi Gov. Haley Barbour pardoned four men convicted of murder, a state official said Monday. David Gatlin, Joseph Ozment, Charles Hooker and Anthony McCray received full pardons and were released at 1 p.m. Sunday, said Suzanne Singletary, spokeswoman for the Mississippi Department of Corrections. All four were serving life sentences and worked as trusties at the governor's mansion, she said. "It is at any governor's discretion," said Singletary. Gatlin was convicted of murder, aggravated assault and burglary of a residence, she said. Ozment was convicted of murder, conspiracy and armed robbery in a separate case. Both inmates were at minimum security level, she said.
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NEW: David Gatlin, Joseph Ozment, Charles Hooker and Anthony McCray are released
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NEW: All were serving life sentences in murder cases
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The four served as trusties at the governor's mansion during Haley Barbour's term
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Families of the victims express outrage at the pardons
@placeholder was convicted in a 1991 murder, while McCray was convicted in a 2001 murder, Singletary said.