CHARLOTTE, N.C. -- Maryland State Police said Wednesday that an autopsy shows Monroe teenager Phylicia Barnes was killed.
The medical examiner listed the 16-year-old's manner of death as "homicide."
Police said the medical examiner also determined a cause of death, but investigators are not releasing that information.
In a statement, police said, "To release a cause of death at this time could jeopardize the investigation by revealing information known only to the person or persons responsible for her death. The cause of death will be made public at an appropriate time in the future."
Barnes' body was found in a Maryland river nearly four months after she went missing while visiting family in Baltimore.
The family has planned a private funeral service for Saturday at the Springfield Baptist Church in Conyers, Ga. The service can be viewed online at http://www.sbclive.org.
The 16-year-old from Monroe went missing Dec. 28 while visiting family in Baltimore. Police worked to keep the search for Barnes in the public's consciousness, but none of the scores of tips they received panned out. Two weeks ago, workers at the Conowingo Dam spotted Barnes' body in the Susquehanna River.
A memorial service for Barnes is set for May 14 at Mount Pleasant Church in Baltimore.
(The Associated Press contributed to this report.)