The penalty phase begins Thursday in the death penalty trial of Tracen Franklin, a 20-year-old man convicted of murdering Bobby Tillman two years ago — a crime that drew national attention because of its randomness and viciousness.

The Douglas County jury delivered an unexpectedly speedy verdict Wednesday. Jurors were sent to deliberate around 2:45 p.m., and about an hour later asked the judge to again go over the definitions of malice murder and felony murder, the two charges against Franklin. By 4:30 p.m. they had made a decision: guilty on both counts. They rejected the option of convicting Franklin of the less serious crime of involuntary manslaughter, which carries a punishment of one to 10 years in prison.

So far, two men have been convicted of murdering Tillman — Franklin and Emanuel Boykins, who pleaded guilty last spring to throwing the first punch to avoid a death penalty trial.

Two other suspects, Quantez Devonta Mallory and Horace Damon Coleman, have not yet gone to trial for murder. Douglas District Attorney David McDade is not seeking the death penalty against them.

Franklin was an 18-year-old student at Alabama State University in 2010 when he took part in killing Tillman.

Prosecutors will present evidence Thursday to support their contention that Franklin should be sentenced to death. And Franklin’s attorneys will call witnesses in hopes of persuading the jury to recommend either life with the possibility of parole after at least 30 years in prison or life without parole.

Douglas County Superior Court Judge William McClain told the jurors they could expect the penalty phase to last until the middle of next week.

Neither McDade or Tillman’s mother, Monique Rivarde, would comment on the verdict because the trial is continuing. Franklin’s mother, Sonia Barber, stared ahead, unmoving, when the verdict was announced. Her son, his head already down, dropped his shoulders even more when he was pronounced guilty of murder.

Tillman, a freshman at Perimeter College in 2010, had been invited to a celebration for two former classmates who had made good grades. The party was to have been small. But word of the gathering spread, and the number of teenagers who descended on the house on Independence Drive swelled to 60 or more before parents shut it down.

According to witnesses, two teenage girls began fighting over a boy. As the teenagers left the house, the girls continued to fight on the lawn and soon there were at least two other fights between girls.

Boykins was trying to break up one of those fights when he was hit by one of the girls. Witnesses said Boykins announced that he didn’t hit girls, so he would “pop” the next guy he saw instead.

Tillman was just a few yards away, sitting on the trunk of his friend’s father’s Mercedes.

Boykins ran up the hill with his friends behind him, knocked Tillman to the ground, and then he, Franklin and allegedly two others punched, kicked and stomped Tillman.

About 30 seconds later, one of those blows caused a fatal tear in Tillman’s heart, a rare occurrence, according to the medical examiner. Prosecutors concede there is no way to know who was responsible for that blow.

Franklin’s attorney, Bruce Harvey, acknowledged that Franklin was part of the attack on Tillman. But there was no intent or malice, he said in his closing argument to the jury Wednesday morning.

“We know Tracen Franklin didn’t start it and we know he didn’t finish it. He’s the guy that ran away while the other people continued to stomp Bobby,” Harvey said. “Tracen Franklin did not deliberately kick the life out of Bobby Tillman.”

Franklin admitted in a videotaped interview that he attacked Tillman. And the detective asked what Tillman had done to cause the attack.

“He didn’t do nothing,” Franklin said in the video that was played for the jury. “He didn’t have to do nothing. He was just there.”