East Lyme — Students at the Niantic Center School sheltered in place for about 12 minutes Thursday, apparently based on a rumor of a missing York Correctional Institution inmate.

East Lyme Assistant Superintendent Amy Drowne said parents were being notified of the incident, which was based on a false rumor. She declined, however, to discuss what that rumor was.

Karen Martucci, a spokeswoman for the state Department of Correction, said a recount of inmates at York was taken on Thursday based on what she described as a miscount that showed at least one missing inmate. The recount showed no missing inmates, she said.

No official communication of the recount was made to town officials, Martucci said.