A grand jury indicted a man Thursday in the murder of Phylicia Barnes, the 16-year-old who disappeared from her sister's apartment in Baltimore in December 2010 and whose body was found last April, according to Gregg Bernstein, the state's attorney for Baltimore City.

Michael Johnson, the ex-boyfriend of Phylicia Barnes' half-sister, is being held at the Baltimore City Detention Center on a charge of first-degree murder, Bernstein said at a press conference Thursday afternoon.

Johnson was arrested at 11:30 p.m. on Wednesday, according to The Baltimore Sun.

Johnson was the last person to see Barnes alive and was also someone whom Barnes' parents told The Baltimore Sun they suspected in her disappearance.

"Based on a complete and very thorough investigation...we believe that we've got the right guy," said Bernstein.

Barnes, who was an honors student residing in North Carolina, had been visiting her half-sister on Reisterstown Road in Baltimore when she went missing Dec. 28, 2010.

In the months that followed her disappearance, area agencies conducted searches, including an investigation in Patapsco State Park.

Barnes' body was discovered in the Susquehanna River by people working on Harford County's Conowingo Dam on April 21, 2011. An autopsy indicated her death was a homicide.