A Brentwood man is being held without bail Friday after being arraigned on second-degree murder and other charges in the death of his 5-month-old son.

Prosecutors say 26-year-old Julio Rivera, who recently moved from Brentwood to Virginia, shook and beat Eric Rivera to death in March. Suffolk Assistant District Attorney Nancy Clifford says an autopsy reveled acute, chronic and recurrent head trauma consistent with shaken baby syndrome. Rivera is also accused of blowing PCP-laced marijuana smoke in the infant?s nose and mouth to stop him from crying. Clifford says the child was repeatedly exposed to PCP and marijuana consistent with levels ordinarily found in adult users.

Rivera pleaded not guilty to the murder charge, in addition to charges of second-degree manslaughter and endangering the welfare of a child. He adamantly refutes the accusations of abuse. Defense attorney Michael Brown describes Rivera, who has a long criminal history and no employment record, as a good father.