The incident took place Thursday evening at the library at 53 Croton Ave, said Ossining Police Chief Kevin Sylvester.
The woman called police right away and officers were able to arrest Jeffrey Wrightman of White Plains. Wrightman, a science teacher at Somers High School since 2004, has been placed on administrative leave.
He was arraigned on Friday and released on $1,000 bail, the chief said.
"We’ve been in contact with District administration throughout the day and we’re doing everything within our power to ensure the safety of our community and their students," Sylvester said on Facebook.
Sylvester said there is some indication that incidents of this type may have occurred in other libraries around Westchester and is encouraging anyone who may have been a victim to contact Ossining Police at 914-941-4099 or the police department in the town in which it occurred.Click here to follow Daily Voice Poughkeepsie and receive free news updates.