After seeing news reports, Lewis said he confronted Kidada Savage, whose brother, accused drug lord Kaboni Savage, ordered the attack. "Why didn't you tell me there was kids in the house?" Lewis said he asked.
Her reply, according to Lewis: "F--- them."
An admitted hitman, Lewis testified publicly for the first time about his crimes, including the fire that killed four children and two adults in what authorities have called one of the most heinous acts of witness retaliation in city history.
Inside the home were six relatives of Eugene "Twin" Coleman, a longtime friend and close associate of Savage's who had agreed to cooperate against him in a federal investgation.
The fire killed Coleman's mother, Marcella; his cousin Tameka Nash; and four children, including Coleman's 15-month-old son, Damir Jenkins. As it happened, Coleman's twin brother was not at home at the time of the attack.
"Did you commit those murders at the direction of somebody else?" Assistant U.S. Attorney John M. Gallagher asked Lewis.
"Yes," he said. "Kaboni Savage and Kidada Savage."
That exchange was near the beginning of what could be days of testimony by Lewis, a pivotal witness in the federal murder and racketeering trial that began in February against Kaboni Savage, his sister Kidada and two others, Steven Northington and Robert Merritt.
Prosecutors say Kaboni Savage ordered the bombing from prison, that his sister Kidada passed along instructions and helped plan it and Merritt, who is Lewis' cousin, was the man who tossed the gas cans into the house.
Lewis said he was promised $5,000 for the hit but Kidada Savage only paid him $2,000. Another drug crew member chipped in about $5,000 worth of PCP oil and a few ounces of cocaine to resell. As for his cousin, Lewis gave him $500 and a used car, he said.
Savage, 38, who is already serving a 30-year term for drug trafficking, is accused of directing or carrying out those killings plus six others, mostly of rival drug dealers. He, Merritt and Northington, an alleged enforcer accused in another murder, face death if convicted. Kidada Savage faces life in prison.
Both sides had portrayed Lewis as possibly the most critical trial witness, the linchpin on the firebombing. For prosecutors he was the vital and credible insider, someone who had confessed to 11 killings, including several that had been unsolved.
Gallagher asked why he decided to cooperate. "Different reasons," Lewis explained. "So I won't face the death penalty. For the victims and their families. So I can show my kids that what I was doing was wrong."
For defense lawyers, he's an assassin whose crimes and desire for self-preservation make his testimony worthless. Under his plea agreement, Lewis could be spared the death penalty but faces at least 40 years in prison. His family has been placed in witness protection.
As he began his cross-examination late Monday, one of Kaboni Savage's lawyers noted that the firebombing didn't come close to ending Lewis' drug dealing, his crime or willingness to use a gun.
"Was that the last murder?" attorney William Purpura asked.
"No, sir," Lewis replied.
On the witness stand, Lewis, 36, looked like an enforcer, wearing a green prison jumpsuit over a linebacker's frame and tattooed forearms. Though he appeared to sniffle and wipe a tear while discussing the Coleman attack, he delivered most of his answers in a flat, almost monotone, voice.
Lewis said he didn't venture into the drug trade until he was 15 or 16, when a dealer in his neighborhood, at Eighth and Butler streets, offered to take Lewis and his girlfriend to Great Adventure theme park - and gave him a job selling $2 crack vials. Later, he landed jobs at a Center City Mellon Bank branch and at the Convention Center. But at night, he'd return to the neighborhood and sell drugs.
Savage was a friend who enlisted him in the drug operation, and later gave him his own block to control.
In time, Lewis also developed a reputation as Savage's muscle. Lewis described two murders he committed on orders from Savage."I don't ever question him," he testified. "That's what I do for our team."
He also worked for others. In 2007, Lewis said, he agreed to kill a 24-year-old woman who had been trying to extort his best friend's uncle. The uncle was a paraplegic but also a drug dealer in Southwest Philadelphia, according to Lewis.
The woman, Tiffany Summers, had tied the man to his wheelchair, sliced him 100 times and poured bleach on his wounds while demanding his money, Lewis said. The uncle wanted revenge, with one condition.
"He wanted me to shoot her in the face," Lewis told the jury.
So he did, and got $8,000 in cash and had his legal fees paid.
At the time of the attack, Coleman was behind bars. The order to attack his family was not a surprise, Lewis said. Coleman lacked the penchant for violence that the others had, he said, and became a likely cooperator after gang members were indicted on drug conspiracy charges.
"Everybody thought that Twin was weak," Lewis said.
He and other members of Savage's drug ring had made a pact, he said, vowing to target the mother of any member that turned against the others.
Lewis took the words to heart. Across his stomach the words "Ride or Die" are tattooed in large green letters. "Riding" means taking your chances, as the other defendants have been doing in the trial before U.S. District Judge R. Barclay Surrick.
Lewis is on the other side now.
"I guess I'm the one dying," he said, "because I'm testifying."
His testimony is scheduled to resume Tuesday.
Contact John P. Martin at 215-925-2649, at firstname.lastname@example.org or @JPMartinInky on Twitter.