She was arrested last year in Philadelphia, and police later searched her apartment in the 1600 block of Fairmount Street. Authorities found an AK-47 assault rifle, 1,000 rounds of ammunition, and several cartridge clips.
A New York jury acquitted Johnson of the attempted-murder charge after her attorney argued that she could not have been identified in the dim light where the alleged ambush of Gross took place.
"It was jury nullification," Gross' attorney, Mark Gimpel, said of the verdict.
But Gross argued yesterday that Johnson, who lives with her mother in Virginia, remained a danger to him and to society in general, especially as her acquittal means she can legally buy a gun again.
Standing at Seventh and Market Streets in front of the U.S. District Courthouse, Gross and Gimpel called on U.S. Attorney Laurie Magid to prosecute Johnson on a charge of possession of an automatic weapon while a fugitive.
A spokesman for Magid refused to comment on whether the case was being reconsidered. Though Johnson was acquitted of the attempted-murder charge, she was not prosecuted on the weapon charge.
Federal law prohibits fugitives from buying or possessing firearms.
Barbara Montgomery, president of the Pennsylvania chapter of the Million Mom March, said automatic weapons represent a clear and present danger to society.
"Even though it happened in New York, it affects people everywhere," Montgomery said.
Contact staff writer Dwight Ott at 215-854-2797 or email@example.com.