Police said last year that four people found executed in a West Philadelphia rowhouse basement were slain because their killers wanted to steal a stash of drugs to resell. On Tuesday, a man allegedly involved in the transaction revealed how much was made from the bloodbath: $105.

Nasir Moss Robertson, whom police initially charged as a participant in the quadruple homicide, testified at a preliminary hearing for one of the accused shooters, Keith Garner, that Garner contacted him after the killings to sell the stolen drugs.

According to Robertson, Garner gave him three bundles of heroin to wholesale in return for $105. Robertson said he hoped to sell the batch to another dealer for $120, earning $15 in profit.

He added that he used some of the heroin after Garner gave it to him, and that it was a “bad” batch that did not get him high.

The grim revelation offered the clearest explanation yet for why four people — Tiyaniah Hopkins, 20; her sister Yaleah Hall, 17; William Maurice Taylor, 31; and Akeen Mattox, 28 — were shot dead in a killing that claimed more victims than any other homicide in the city last year.

After Garner’s hearing, Municipal Court Judge Wendy L. Pew held him for trial on murder and related counts. Two others charged in the crime, Jahlil Porter and Robert Long, are awaiting trial after previously waiving their preliminary hearings.

Murder charges against Robertson were dropped in April after he provided information to prosecutors, who came to believe he did not participate in the killing but only the attempted drug sale afterward. Robertson is awaiting trial on drug-related charges for those alleged actions, although he testified Tuesday that he ended up selling just one of the bundles.

The others were seized by detectives after he was questioned by police and he told them where to find the stash, he said.

Jalaya Murphy, 21, testified Tuesday that she had been dating Garner at the time of the murders, Nov. 18, 2018.

Murphy said that Garner sent her a text message that night with a picture of a gun. In the message, Murphy testified, Garner said he was going to “go handle Will,” an apparent reference to one of the victims, Taylor.

Later that night, Murphy said, Garner came home with two other people, then told her they had taken drugs from Taylor’s house in the 5100 block of Malcolm Street. Murphy said Garner described taking Taylor and Mattox into the basement, then finding two women upstairs, one of whom was calling 911.

Murphy said Garner told her that he and his coconspirators walked the women into the basement, at which point Taylor started yelling for help.

“Once Will started screaming, he shot Will,” Murphy said, recalling what Garner told her. She said Garner told her that Porter fired at the victims as well.

All four victims suffered gunshot wounds to the head. Taylor was shot three times, according to records presented by prosecutors Danielle Burkavage and Jason Grenell.

Garner’s attorney, Coley Reynolds, sought to point out Tuesday that Murphy continued dating Garner even after he allegedly confessed his role in the killing to her, and after he was arrested and imprisoned as an accused murderer.

Meanwhile, Mattox’s friend Steven Baxley testified that he had been hanging out at Taylor’s house on the afternoon before the killings. Baxley said he picked up on the idea that Mattox was about to engage in a risky drug deal, so he tried to talk him out of it.

“We all come to an agreement,” Baxley said. “This was a bad idea."

Baxley said he left the house thinking the deal had been called off.

The next day, Baxley said, he learned that Mattox and the three others had been found dead in the basement.