Prosecutor John Meadors argued in court Thursday that Alex Murdaugh's drug use doesn't explain his lying to police and general behavior on the night of his wife and son's killings.
Murdaugh has admitted he lied to investigators about whether he had been to his estate's dog kennels shortly before their deaths, blaming paranoid thinking stemming from his opioid addiction.
Responding to the defense's closing arguments, Meadors said that explanation doesn't stand up to a test of common sense. He implored the jury to think about the video they watched of Murdaugh's initial interview with law enforcement on the night of the killings.
"Tell me what he was like in that car, you've got the video," the prosecutor said.
Meadors said the video showed Murdaugh appearing to understand questions, making timely answers and responding appropriately.
"Was he in his right mind? Of course he was," the attorney said.
Meadors also argued that if Murdaugh had taken the number of pills he claimed to have taken, "he'd be dead."
"You can't take that many pills," the attorney said. "That's your common sense."
Some context: Murdaugh said he sometimes took more than 2,000 milligrams of oxycodone per day in the months leading up to the deaths of his wife and son.
It is virtually unheard of for a doctor to prescribe a patient more than 100 milligrams of oxycodone a day, even for the most severe acute or chronic pain.
While 2,000 milligrams sounds astronomical in comparison, taking that much daily is medically possible, according to CNN Chief Medical Correspondent Sanjay Gupta.
CNN's Elizabeth Wolfe contributed to this report.