Officials would not release details other than to say that the incident did not appear related to terrorism or ongoing criminal activity, according to Chief Inspector Joe Sullivan of the Homeland Security Unit.
Still, residents were shaken, and the nearby Carnell School was placed on lockdown.
"I can't believe it happened in my neighborhood," said Amy Devor, who said she has lived on Shisler since 1992.
Police arrived shortly after 9:50 a.m. after a woman noticed a box of cylindrical devices in her basement, Sullivan said. The woman told police that she did not recognize the box and did not know how it got there, but was sure it contained bombs.
"It was something that anyone who looked at would be immediately concerned," Sullivan said.
A preliminary search of the house found nothing to indicate where the bombs came from, and investigators were attempting to track down former residents, Sullivan said.
"Right now we can't ascribe any potential motive" for the bombs' manufacture, Sullivan said.
"Our first priority was to render the scene safe," he said. "Now that that's done, we are going hard into the investigation."
Steve Bartholomew, an agent of the federal Bureau of Alcohol, Tobacco, Firearms, and Explosives, said only one of the bombs appeared to be functional.
The Bomb Squad detonated one of the six in a controlled explosion.
Neighbors said they heard the explosion and saw smoke rising from behind the rowhouses on Shisler.
"They dragged it out and yelled, 'Fire in the hole,' " said Raymond Ortiz, who lives a block away on Frontenac Street. "It sounded like a real bomb."
On Thursday afternoon, police and ATF agents were still walking in and out of the house as its occupants, a middle-aged man and woman, sat on the front stoop.
Neighbors called them quiet residents who kept to themselves. Both declined to comment.