Suspicious packages were sent this week to election offices in more than 20 states, leading to an FBI investigation, triggering evacuations and rattling staff, according to a CNN survey of state offices and Associated Press reporting.

The FBI and U.S. Postal Service are investigating suspicious packages that have been sent to or received by elections officials in at least eight states.

A suspicious package has been sent to the California secretary of state, as well as election officials in at least 15 other states. No one has been hurt.