A Prince George’s County Circuit Court judge on Monday declared a mistrial in the long-awaited case of a suspected serial killer charged with strangling a mother and daughter in Largo, authorities said.

Prosecutors said a “technical error” led Judge Michael Whalen to declare a mistrial in the case against Jason T. Scott, now 30, who is accused of attacking the pair during a home invasion.

John Erzen, a spokesman for Prince George’s State’s Attorney Angela Alsobrooks, said the error came when an agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives, under prosecutors’ questioning, referenced “multiple” additional home invasions that Scott was involved in. Whalen, Erzen said, had previously ruled that prosecutors could present evidence of a single other home invasion, and he ruled that the agent’s remarks might unfairly prejudice jurors.

“While it’s certainly disappointing, we feel that it was the right ruling,” Erzen said. He said a new trial is scheduled for October.

Scott faces first-degree murder charges in the March 2009 slayings of Delores Dewitt, 42, and her daughter, Ebony, 20. Prosecutors have said that Scott went inside their home, strangled the women and sometime later set a stolen car on fire with their bodies inside. Police and prosecutors have characterized Scott as a cunning serial killer. He is suspected — although not charged — in the 2009 slayings of Karen Lofton, 45, and her daughter, Karissa, 16, in Largo and in the 2008 killing of 46-year-old Vilma Butler in Bowie, police have said.

Scott, who will remain jailed, was sentenced last year to a century in prison in a separate, federal case in which he was convicted of orchestrating home invasion robberies and other crimes.