YOUNGSTOWN, Ohio -- A grand jury handed up a 29-count indictment yesterday of Michael A. Davis, the teenager accused of killing six people by burning down a house, and prosecutors will seek the death penalty.

Mr. Davis -- who turned 18 in December, making him barely eligible for the death penalty in Ohio -- is charged with aggravated murder in causing the deaths of four children, ages 2 to 8, their mother and grandmother in a Jan. 23 fire. He picked up four additional charges for aggravated murder of a juvenile under 13.

All 10 murder counts came with a death penalty specification.

"It's a tragedy that this act occurred," said Mahoning County Prosecutor Paul Gains.

"We have to address it. I think that especially these young people have got to be made to realize that there are consequences for their actions. And in this case, these are the most serious of consequences."

Killed were Carol Crawford, 46; her daughter, Jennifer R. Crawford, 23; and Jennifer's children, Ranaisha, 8, Jeannine, 5, Alisha, 3, and Brandon Owens, 2.

Mr. Davis, who was arrested the day of the fire, also is charged with 19 counts of aggravated arson for the 11 people in the house -- five of whom escaped -- and eight injured Youngstown firefighters. The most seriously injured firefighter received five stitches.

Investigators have said the arsonist poured an accelerant on the front porch, causing the two-story wood house to burn quickly.

A possible motive for the arson was a stolen cell phone. After Mr. Davis, who lives around the corner from the Crawford home, lost his phone he called the number and one of the people in the house, not one of the deceased, answered it, authorities have said.

Mr. Davis' court-appointed lawyer, Martin Yavorcik, said this week that Mr. Davis is illiterate but understands that he will face the death penalty.

If Mr. Davis is convicted of any of the murder charges but the jury does not find for the death penalty specifications, Mr. Gains said, Mr. Davis would face a sentence of 25 years to life, 30 to life or life without parole.

"As swift as this indictment came out and as swift as the investigation was done," Mr. Gains said, "it's pretty much proof positive that we're not taking any of these charges lightly."