Flumo, a District resident, was sentenced to 234 years in prison, and Sumo, 29, of Takoma Park, was sentenced to 214 months for their roles in a string of armed robberies targeting gas stations, liquor stores, convenience stores, and restaurants in the region.
Prosecutors say that Flumo, Sumo, and Enyinna "Reggie" Onyewu, 31, of Silver Spring, were convicted earlier this year after being found guilty in US District Court on conspiracy, robbery, and weapons charges.
It was alleged that Onyewu took part in five of the robberies; Sumo in seven of the robberies; and Flumo in all 10 of the robberies.
In January 2018, court documents state that the three worked together during their crime spree, each time threatening employees with a .45 caliber handgun, wearing masks and gloves to avoid being identified by investigators.
During several robberies, they physically assaulted store employees and put the gun directly to the heads of their victims at random hours, including some in broad daylight.
"The victims were left shaken and shocked by the incidents," officials said. "Fortunately, none of them sustained serious physical injuries."
At trial, more than 30 witnesses testified against the trio.
Targets during the crime spree included locations in Silver Spring, Takoma Park, Northwest DC, and Arlington, Virginia.
Onyewu was arrested on Oct. 22, 2020; Sumo on Nov. 23, 2020, and Flumo on Apr. 27, 2021. "Reggie" was sentenced Aug. 18, to 166 months in federal prison followed by 36 months of supervised release
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