Knapp was convicted of killing Lawson Aug. 19, 2011 at the cemetery behind Newark Baptist Church. Lawson was found by her boyfriend on the afternoon of Aug. 20, beaten to death.
It was alleged by Lawson's boyfriend, Patrick Lewis she had left his residence on Newark Road around 4 p.m. on Aug. 19, and when she did not return after a few hours he went to look for her, unsuccessfully.
When Lawson still did not return home, Lewis went to look for her again Aug. 20 and located her body, yards from the grave of her little brother, Brandyn, and called 911.
The jury, consisting of 10 women and two men, went into deliberation around 4:45 p.m. and returned to the courtroom with a verdict at 7:45 p.m.
Several witness testimonies declared Knapp blamed Lawson for the death of his step-son, Jeffre Alan Sims -- who had died two weeks prior from an apparent suicide.
During the closing arguments Tuesday morning, Greene County Prosecutor Jarrod Holtsclaw told the jury, "This man right here (Knapp) beat the life out of Stacey Lawson for no reason, and had the nerve to do it feet from her little brother's grave."
He recounted witness testimony from Brian Patton and Brittany Lake, in which Knapp allegedly told Patton in detail what he had done to Lawson and Lake was able to hear the description as well.
Defense co-counsel David Hunter alleged Patton and Lake didn't go to police immediately in order to continue to hide their admitted drug addictions.
"The defense wants you to think they made this up to get out of trouble. They told us they gave him the meth. They told us the truth," Holtsclaw said during his rebuttal.
Hunter asked the jury if the state had proved Lawson was murdered, to which he replied yes.
"But, has it been proven he (Knapp) had killed Stacey Lawson?" Hunter added.
Hunter also raised question about why Lewis was not investigated further, noting there was no search warrant issued for Lewis' phone records, clothing, home or truck.
He added it appeared police believed Lewis from the beginning and based their investigation off his recount of the night Lawson went missing.
"From that point on everything was directed toward the defendant. Let's build the case around the defendant," Hunter claimed.
The defense also noted Lewis' possible motives to possibly kill Lawson to the jury, noting he could have been upset by the fact she was drunk and on some form of drugs.
Hunter reminded the jury Lewis said during his testimony staying away from drugs and people from her previous life had been his main stipulation on her living in his home.
Lewis had also mentioned the couple had plans to go out and eat Friday night, then go look at engagement rings Saturday.
"Here she is drunk, using drugs, and -- Bingo -- Randy Knapp is in the picture. He comes home and he has been betrayed," Hunter said.
Hunter also pointed out to the jury when Lawson allegedly took off running out the door without her purse and cigarettes, possibly she was running from Lewis.
Holtsclaw replayed the voicemail messages left on Jeremy Walker's cell phone by Knapp, four of which were left the night Lawson went missing.
Knapp stated in a message left, at 3:16 p.m. Aug. 19, he was on his way to Greene County to see "somebody," but added, "I'm not going to say who in case something happens."
In the voicemails, Knapp referred to himself as raged and crazed, and mentioned multiple times he was high on methamphetamine.
"That was the real Randy Knapp ladies and gentlemen, and I feel like you needed to hear that again today," Holtsclaw said in reference to Knapp's demeanor in the messages.
Holtsclaw also referenced a portion of one voicemail where Knapp said, "I may just beat her brains out."
"You saw the pictures. He beat her, drug her from the grave, and he did what he told you he was going to do -- he beat her head in," Holtsclaw said.
The jury will return at 8:30 a.m. Wednesday to hear the second phase of the trial to decide if Knapp will be sentenced to life in prison without parole.