Malcolm was shot multiple times and died at the Hospital of the University of Pennsylvania. Police believe Bennett was shot in the living room and dragged himself to the basement, where he was found dead.
Inside the house, investigators found $102,000 in cash; "a large amount" of expensive narcotics such as Percocet, Xanax, and morphine; a smaller amount of hydroponic "designer" marijuana; a few prescription-drug pads; and two semiautomatic guns and two revolvers, according to Capt. James Kelly.
The mother, Cynthia Bennett, was out of the house at the time of the shooting, and the father, Rohan Bennett, was upstairs with an 18-year-old family friend, Clark said. All three have been questioned by police, and Clark said the parents were likely to face drug charges.
Lt. Walt Bell, who is handling the investigation, said the 17-year-old and his parents were intended targets of "a dispute over narcotics or money." According to other police sources, Malcolm has had three prior convictions on drug charges.
The details obtained from police contrasted sharply with the neighborhood's quiet reputation and friends' descriptions of the victims. Early Wednesday afternoon, the only sign of the crimes inside the two-story brick rowhouse was a remnant of yellow police tape peeking out from the bushes.
Two girls, both 17, who were friends with Malcolm came by to leave teddy bears on the family's lawn - a big one with "RIP Chris" scrawled in black marker, and a smaller one that said "RIP Sonny." The girls, who said they live in the neighborhood but did not want to be named, said the victims had a "tight brotherly bond."
"They were nice. Alive, funny, sweet. Chris' little brother looked up to him," one girl said.
One card included the message "RIP from Frank and all my soldiers."
Bysil Doe, 17, said he was one of the few friends who was allowed inside the Bennett home. There also was a third brother, age 8 or 9, and Malcolm "was always taking care of his brothers when his parents were at work," Doe said, adding that they seemed like a typical family.
Doe and other friends, who declined to be named, said Malcolm and Sonny Bennett were honor-roll students and liked to ride dirt bikes. Malcolm also played on the Lamberton School basketball team, Bysil said, and was "not no big drug lord."
Another friend of Malcolm's who did not want to be named said the deaths did not yet seem real.
"I just saw him yesterday," the 18-year-old said. Malcolm was driving. They exchanged a quick "what's up" and agreed to catch up later. "I still think it didn't happen," the friend said, "it was a dream."
Numerous neighbors on the 1300 block of Westbury Drive said they had not noticed anything suspicious.
Rene Langford, 28, lives a few doors down, but had never met the family. She said they were always quiet and didn't come out much.
"It was a nice, normal house ... in a quiet neighborhood," said Langford, whose 5-year-old son was playing out front at the time of the shooting. "This doesn't happen around here."
Janice Wilson, a member of the civic association who has lived in Overbrook Park for decades, said this type of violence was "totally not normal here."
"Some mother's babies are dead. It's a tragedy," Wilson said. She said she worried that the deaths will give the community a bad reputation. "We need to join together tighter as a neighborhood and not be afraid."
Contact Jessica Parks at 215- 854-2771 or firstname.lastname@example.org.
Inquirer staff writers Julie Zauzmer and Mike Newall contributed to this article.