David E. Maust, the Indiana man suspected of murdering three teenagers found buried in his basement, pleaded not guilty Friday to charges that he strangled and killed a 16-year-old boy.

The 49-year-old also told the judge that he wants to represent himself in court. A hearing on that request will be held next Friday.

Maust, known by his neighbors as "Crazy Dave," was only charged with the murder of James Raganyi, 16, though officials said there was an ongoing investigation into the deaths of the other two teenagers, identified by Lake County (search) Coroner David Pastrick as those of Michael Dennis, 13, and Nick James, 19.

The single murder charge was filed Thursday against Maust, 49, a tenant of the rundown apartment house in Hammond from which investigators this week removed the bodies of the three adolescents, who had been reported missing in recent months.

To view the charge against Maust, click here (pdf file).

Maust, who has been in police custody since Tuesday, has a criminal record that includes a murder conviction for the death of a 15-year-old boy in Illinois and a conviction in Texas for committing bodily injury to a child, police said.

During the brief arraignment hearing Friday in Crown Point, Maust looked around the courtroom, and he appeared to smirk as he was escorted out.

Dennis and Raganyi were last seen Sept. 10 at a home near where Maust lived in the northwestern Indiana city.

About three weeks later, on Oct. 2, police arrested Maust on a charge of contributing to the delinquency of a minor, alleging he had given Dennis and a 12-year-old boy marijuana (search) and beer at his home during August. Maust was released on $300 bond the same day and later pleaded innocent to the charge.

Dennis and Raganyi were friends and had visited Maust in his second-floor apartment, where he had given them money, beer and marijuana during the summer, a friend of the boys told detectives.

James was last seen in May but reported missing two weeks ago. He died of blunt trauma to the head, Pastrick said, but strangulation or suffocation were the suspected causes of death for the younger teens.

Maust confessed to strangling Raganyi with a rope while drinking with the teen Sept. 10, a police affidavit said.

Lake County Prosecutor Bernard Carter declined to say whether any sexual abuse was involved.

Police Chief John Cory would not say whether Maust had talked about the deaths of Dennis and James, or whether investigators suspect anyone else was involved in the slayings.

The link between Maust and the two younger teens caused detectives to search the house last month, where the fresh 8-foot-by-5-foot concrete pad was found in the basement.

Holes were first drilled through the 12-inch thick concrete last Friday. Further digging on Tuesday revealed two of the bodies, wrapped in plastic and tied with cords and tape, a police affidavit said. The third body was removed Wednesday.

Investigators completed their search Thursday for bodies in the house where Maust had lived for about 15 months, said Sgt. Christopher Matonovich, a city police spokesman.

Maust has a checking account with $2 in it, no car and no source of income.

Lynn Smith and Don Smith — Raganyi's mother and stepfather — told Fox News they learned Thursday that their son's body had been found. James Raganyi was last seen in September.

"I spoke to him the day before he ran off, before he was going to school, he told me he loved me and I told him I loved him and that was the last time I'd seen or heard from him," Lynn Smith said. "This is a mother's worst nightmare ... you never thought in your life that something like this would happen to you."

Lynn Smith said she was doing television interviews to "get a message out there for other kids [and] parents ... to be aware" of individuals who may pose a threat to children.

Don Smith said community members everywhere needed to call police with reports of any suspicious activity. Maust had approached several other young male teens in the neighborhood and offered them alcohol and drugs, according to community members.

"I'm not blaming anybody — the only person I'm blaming is Maust," he said. "I don't know what he is but I know he ain't human ... he isn't alright ... this man has done this a lot of times."

The Associated Press contributed to this report.