The senator’s office issued a statement suggesting that the timing of the indictment was politically motivated — she faces a strong challenger, James Sanders Jr., a city councilman, in a Democratic primary on Sept. 13. “Senator Huntley has been an advocate for parents and children in this community for over 40 years,” it said, “and, rest assured, she will continue representing the 10th Senatorial District.”

The charges against Ms. Huntley included tampering with evidence and falsifying business records, both felonies that carry maximum sentences of four years in prison, and conspiracy in the fifth degree, a misdemeanor. If convicted of a felony, Ms. Huntley would automatically be removed from office.

As a result of the indictment, Ms. Huntley was stripped of her leadership positions and committee rankings. She was the ranking Democrat on the Senate’s Committee on Mental Health and Developmental Disabilities, a role that carried a $9,000 stipend, which she had already received.

The charges were filed by Attorney General Eric T. Schneiderman in Mineola because the nonprofit agency lists a Nassau County address as its headquarters.

Also charged in the case were a niece of Ms. Huntley’s, Lynn H. Smith; Patricia D. Savage, Ms. Huntley’s aide, who like Ms. Smith is an officer of the nonprofit agency; and David R. Gantt, a former aide to Ms. Huntley. Ms. Smith and Ms. Savage are accused of stealing nearly $30,000 from the group and were charged with multiple counts of grand larceny. Mr. Gantt, who was described as a consultant to the group, was accused of falsifying documents. The three had already been charged in a previous indictment last year; the new charges were part of a superseding indictment.