The incident occurred Jan. 10 while the girl and her friends were waiting in line for a school bus, PennLive.com reported.
"I'm going to shoot you and I will shoot myself," the girl allegedly said in reference to the toy that shoots out bubbles, said Robin Ficker, a Maryland lawyer representing the girl's family.
The girl was labeled a "terrorist threat" by the school and suspended for 10 days, Ficker said.
"This little girl is the least terroristic person in Pennsylvania," he said.
School district solicitor Edward Greco said Friday the incident was being investigated, but neither he nor school officials could discuss disciplinary actions that may be taken against the girl.
Ficker and the girl's parents have requested the girl's record be expunged and she be offered an apology.