Del. Joseph D. Morrissey, a lawyer who waved an assault rifle on the House floor this year, is the subject of criminal investigation related to a 17-year-old girl whom police found at his home last Friday night.

The girl, a college freshman and part-time receptionist for Morrissey’s law firm, was visiting the delegate to discuss a “very sensitive legal matter,” according to Rob Walker, a Richmond attorney for the girl’s mother.

The girl had her mother’s permission to go to Morrissey’s house and said that “at all times during the visit, Mr. Morrissey was a gentleman and acted entirely in a professional manner,” Walker said.

Police who were summoned to Morrissey’s home last Friday found the girl there and took her to her father, who was nearby, the Richmond Times-Dispatch reported.

The Henrico County commonwealth’s attorney’s office confirmed that Morrissey is under investigation but provided few details.

“There is an investigation involving Delegate Morrissey and it does involve a juvenile,” said Deana Malek, deputy commonwealth’s attorney. “Because of the nature of the case and because it is ongoing, there is no further information at this time.”

Morrissey (D-Richmond) did not respond to a message seeking comment.

Morrissey is a former Richmond commonwealth’s attorney. In January, he held an assault-style rifle aloft on the House floor as he argued in support of tougher gun-control laws.