At a news conference on Wednesday afternoon, police released more details about the killings of 17-year-old Christopher Malcolm and 13-year-old Rohan "Sonny" Bennett.
It was around 7:30 p.m. Tuesday when police were called to the 1300 block of Westbury Drive in the Overbrook Park neighborhood.
Capt. James Clark said that an unidentified male came to the home with the intention of making a drug transaction. That male talked to the teenage brothers, and that's when something went wrong.
Police couldn't say what exactly happened, but the man pulled out a gun and shot Malcom in the living room. Malcolm later died at the hospital.
The gunman also shot Bennett, who managed to run into the basement. He was pronounced dead at the scene.
Witnesses told police they saw a man fleeing the home with a large bag. He was only described as a man with a light complexion wearing a blue shirt.
As police searched the home, they allegedly found $102,000 in cash, more than 1,700 illegal prescription pills including Oxycodone, Percocet, Xanax and six large bottles of Codeine. Police say they also found a small amount of marijuana.
Most of the drugs and cash were found in the bedrooms of the boys' parents, police said. Those parents were being questioned and are likely facing drug charges.
"A large amount of narcotics was found, a large amount of money and drugs, so it would be hard for them not to know what was going on in their house," said Capt. Clark.
Police earlier said Malcolm had a narcotics-related record. Friends said Malcolm was a new father.
By Wednesday morning, loved ones began forming a memorial outside the home.
"Just a really unfortunate situation," said neighbor Simaj Johnson. "I'm very sorry, very upset about what happened."
"I don't know what it was over, what it was about, I don't care what it was about. An innocent life, another life in this city, is being taken," said friend Darius Daniels.
Anyone with information is asked to contact Philadelphia police at 215-686-TIPS (8477), text a tip to PPD TIP or 773847, or through phillypolice.com.