The 16-year-old boy sat quietly in the Central Booking courtroom yesterday, surrounded by young adults and middle-aged men, his standard-issue gray sweat shirt and khaki pants covered in writing, the kind of doodles someone his age might scrawl on a notebook in a classroom.

Jerome Williams was ordered held without bail yesterday in the killing of former City Councilman Kenneth N. Harris Sr. The charges against the teenager - who was 15 at the time of the killing in September - include first-degree murder, conspiracy to commit murder, armed robbery and use of a handgun in a violent crime. He is the third suspect charged in the fatal shooting.Despite his youth, Williams is no stranger to the law. At yesterday's hearing, officials listed more than a dozen charges he has faced as a juvenile, dating to at least 2005 when he was 12. His record includes new robbery charges since Harris was shot.

Williams was under the supervision of the Department of Juvenile Services and Social Services, and sources who are not authorized to speak on the record said he had been placed in the state's violence-prevention initiative, meaning he had contact with case workers three to four times per week. In the fall, he was released from a residential treatment facility and was on juvenile probation.

Donald W. DeVore, secretary of Maryland's Department of Juvenile Services, declined to discuss the specifics of Williams' background but said the youth's criminal history represented a "rare case."

"He's someone that had been in our system for quite some time, and we had been responding to his delinquent behavior," DeVore said. "It's not like he was a kid who was out there and not known to us."

The boy did not speak at the hearing, only shifting his glance between the floor and District Judge Christopher L. Panos, who noted the "incredible, most egregious nature" of the charges in denying bond.

Scrawled in black marker on his sweat shirt was "1400 blk, Fenwick Ave, R.I.P." The three suspects in the killing are said to have run down Fenwick Avenue after fleeing out the back of the jazz club where Harris was shot. The street leads to Williams' last known address in the 1500 block of Lochwood Road. The word "Rome," possibly an abbreviation of his first name, was written at the top of his shirt. Other words and abbreviations were written on his pants and shirt.

Williams also had two notable tattoos - one on the left side of his neck that read, "M.O.B." and two red-tinged teardrops under his right eye. Both are widely recognized as gang symbols.

Harris, 45, was fatally shot in the early hours of Sept. 20 after being ambushed during a robbery at the Northwood Plaza shopping center in Northeast Baltimore. Police arrested two suspects, Charles Y. McGaney, 19, and Gary Collins, 20, in November. Both are also charged with murder.

It is unclear how the men might know each other, but charging documents show that homicide Detective Donald Diehl monitored their phone conversations while they were in prison and heard Collins talking about someone with the nickname of "Lil Country." The context seemed to indicate a connection to the killing, Diehl wrote.

Detectives were later contacted by Baltimore County police, who said that while interrogating a suspect in an unrelated case, they were told that the third suspect in the Harris killing was known as "Lil Country."

Diehl then contacted a witness who had identified McGaney and Collins from surveillance video footage and a photo lineup, records show. The witness said Williams was "Lil Country" and picked him out of a photo array.

At a news conference last week, Police Commissioner Frederick H. Bealefeld III said police obtained a search warrant and took a DNA sample from Williams on Jan. 14 while he was being held at the Baltimore City Juvenile Justice Center. Bealefeld said Williams' DNA matched genetic material found on crime scene evidence from the Harris killing.

Court officials said yesterday that Williams has faced charges that include robbery, assault, gun offenses and burglary. He apparently had been in school recently, and was charged with assault on school grounds and battery Sept. 29. On Jan. 6, he was detained on attempted robbery and weapons charges.