Prosecutor James Mayer told the board in his written statement that the girl's injuries were consistent with a homicide that contradicts Smith's claim he didn't intend to kill her.
"The horrific attack upon Autumn Carter showed much more than Smith's stated purpose," Mayer said.
Mayer says he didn't know why Smith wasn't charged with rape, but he said it wasn't part of a trial strategy.
The attack happened early in the morning of Sept. 29, 1998, in the Mansfield apartment of the girl's mother, Kaysha Frye, whom Smith had been dating about six months.
Frye was awakened after 3 a.m. by a naked Smith, who placed Autumn beside her in bed, according to records. Frye realized the girl wasn't breathing, told Smith he'd killed her and then ran to a neighbor's house for help.
Smith, known to consume as many as 12 beers a day, had had several beers the previous evening and had a blood-alcohol content of 0.123, well above the legal limit for drivers, when he was tested almost eight hours later, records show.
Smith had unsuccessfully tried to have sex with his girlfriend the evening before the attack, according to records. The prosecutor argued that Smith's assault of the girl was revenge for Smith's failure to perform with Frye.
Smith's attorneys dispute this, saying the girlfriend was not upset with Smith.
Prosecutors presented evidence at trial that Smith's attack lasted as long as 30 minutes, during which time Smith beat the girl to death.
Expert witnesses for Smith conclude he may have accidentally suffocated the girl within three to five minutes while he lay on top of her, according to Smith's clemency petition.
If executed, Smith would become the 51st inmate put to death in Ohio since the state resumed executions in 1999. The state has enough of its lethal injection drug, pentobarbital, to execute Smith and two other inmates before the supply expires. Eight more inmates are scheduled to die from November through mid-2015.
Andrew Welsh-Huggins can be reached on Twitter at https://twitter.com/awhcolumbus.