The Nashville Public Library closed all branches Thursday after receiving a bomb threat.

Police say officers are investigating the source of an emailed bomb threat, which library staff received just after 10:30 a.m.

Police checked the library’s downtown location at 615 Church Street for suspicious items, but nothing was found.

Officers were sent to check other library branch locations as well.

The library says it nonetheless closed every location for the day, out of an abundance of caution. Normal operations will resume Friday.