A Baltimore man denies killing a teenager who was missing for months before her body was found — a girl he considered a sibling of his own even as he broke up with the teen's half-sister, his attorney said Thursday.

Michael Johnson, 28, was indicted on a count of first-degree murder in the death of Phylicia Barnes, 16, of Monroe, N.C., who went missing in December 2010, Baltimore State's Attorney Gregg L. Bernstein announced.

"The fact that the investigation proceeded for a year before we were able to bring charges put them in some state of limbo, so we do hope it provides some measure of closure for them," the prosecutor said.

Bernstein declined to elaborate on the details of the case other than to say Johnson was the last person to see Barnes alive, but said he doesn't expect more indictments in the case. The fact that Johnson is charged in Baltimore city, indicates that investigators believe the alleged crime happened there and not in Harford County, where her body was found. Bernstein would only say he believes the venue is appropriate.

Johnson maintained his innocence and vowed to fight the charges when he spoke to his attorney, Russell Neverdon, at Baltimore's Central Booking and Intake Center on Thursday.

"He said he had absolutely nothing to do with anything inappropriate or misgivings towards Phylicia that resulted in her disappearance and the untimeliness of her death," Neverdon said. He believes investigators have a circumstantial case against his client and said they even told Johnson during one of several interviews that it was just a matter of time before they got him.

Bernstein said Johnson was arrested without incident, but Neverdon said his client was punched and kicked during his arrest and received medical attention. Police referred questions to the U.S. Marshals Service, which declined to comment.

Barnes' father told The Associated Press that when his daughter disappeared, Johnson had been breaking up with the teen's older half-sister after dating about 10 years.

"It's been a long day coming. It's a bittersweet day," Russell Barnes said. "I can rest better and maybe Phylicia can rest a whole lot better."

The family had trusted Johnson, but he acted suspiciously after the girl disappeared, avoiding people and phone calls, Russell Barnes said.

Phylicia Barnes' half-brother, Bryan Barnes, 24, said Johnson and Phylicia Barnes were close and he would even called the teen "little sister." He remembered playing basketball with Johnson, who was considered part of their family, as he grew up and didn't know Johnson to be a violent person.

Phylicia Barnes was visiting her older half-siblings in Baltimore over the Christmas holidays when she disappeared from her sister's apartment in northwest Baltimore on Dec. 28, 2010. Baltimore police soon alerted local media, saying her disappearance was unusual because she had no history of disputes with her family or trouble with the law.

She was an honor student at Union Academy, a public charter school in Monroe, was on track to graduate early and had already been accepted to several colleges. She had reconnected with her half-siblings on Facebook, and she traveled to Baltimore several times to visit them. Her father said the sisters even talked about living together while the teen attended Towson University.

Her stepfather, who lives in North Carolina, declined to comment on the arrest Thursday morning.

Police, who had help from the FBI, had few leads and called it one of the most frustrating missing persons cases they had investigated. At one point, police spokesman Anthony Guglielmi described it as "Baltimore's Natalee Holloway case," referring to the Alabama teen who disappeared during a trip to Aruba.

Police and volunteers searched area parks in the weeks and months after she vanished and handed out leaflets in the area where she was last seen, but neither turned up any clues. Investigators tried to keep the search in the public consciousness, even posting a smiling photo of Barnes from her Facebook page on electronic billboards along highways in the Baltimore region. They received scores of tips, but none panned out.

Workers at the Conowingo Dam on the Susquehanna River found her body the following April in northeast Maryland. The death was ruled a homicide, but authorities did not release the cause of death.

After Phylicia Barnes' body was found an hour's drive from the Baltimore apartment where she was last seen, state police homicide investigators took over the probe, working with city police investigators.

Later, federal authorities sought access to multiple e-mail and Facebook accounts, including some bearing Phylicia Barnes's name and others that belonged to Johnson, as part of a child pornography and sexual exploitation of children investigation, according to documents and Neverdon. The applications for search warrants remain sealed and no charges have been filed.

The case spurred broader interest in missing persons cases and led to a bill that passed in the Maryland legislature this year called "Phylicia's Law," to improve coordination between law enforcement and community groups when a child disappears.

The process has been long, but Russell Barnes said he was in contact with investigators every week.

"They knew that the family was not going to give up," he said.