An attorney says a wrongful-death lawsuit is planned against an off-duty white St. Louis police officer whom a prosecutor has cleared in the shooting death of a black 18-year-old last October.

St. Louis Circuit Attorney Jennifer Joyce's report, released Monday, says a criminal violation could not be proven beyond a reasonable doubt in VonDerrit Myers Jr.'s death.

The unnamed officer was patrolling a neighborhood as a security officer when he approached Myers.

The report says the officer had reason to suspect Myers was armed, and a chase ensued. Authorities said Myers fired at least three shots at the officer, who returned fire.

An attorney for Myers' family said Tuesday he believes Myers was never armed, and that the family will file a wrongful-death lawsuit within the next two weeks.