Updated

A man convicted of killing a North Carolina teenager and putting her body in the Susquehanna River was ordered freed Tuesday by a judge who dismissed all charges against him.

Baltimore Circuit Court Judge John Addison Howard dismissed second-degree murder and other charges against Michael Johnson, 30, saying the prosecution's "arguably circumstantial" case against Johnson was insufficient evidence.

Baltimore's State's Attorney promises to appeal the ruling.

Johnson was charged in the death of Phylicia Barnes of Monroe, North Carolina. Barnes, 16, vanished in December 2010 while she was visiting relatives in Baltimore. Her body was found months later floating in the Susquehanna.

Johnson was arrested in 2012 and charged with Barnes' slaying.

Prosecutors alleged that Johnson killed Barnes in her sister's apartment and used a 35-gallon tub to move the body.

Johnson was convicted of second-degree murder in 2013. A judge ordered a new trial after ruling prosecutors withheld evidence about a key witness.

Last month, Howard declared a mistrial in Johnson's second trial.

Baltimore State's Attorney Marilyn Mosby said in a written statement Tuesday: "I want to be clear that there was no prosecutorial misconduct in this case. The court agreed there was no misconduct in its prior ruling in December, and again today."

He added that "... the court had no jurisdiction to grant the acquittal and we will be seeking an appeal on those grounds."

The Baltimore Sun first reported Tuesday's decision.