Federal authorities have taken custody of a group of undelivered election ballots found near a dumpster in Renton, Washington, after reports that around 500 ballots from multiple past elections were discovered.

The ballots, which officials say were sent to voters but never retrieved, are now being reviewed by agencies including the FBI and the U.S. Postal Inspection Service.

The discovery sparked concern from some officials about election security, but King County Elections said there was no evidence of fraud or misuse.

Election officials criticized the decision to publicize the find instead of immediately reporting it to authorities, KOMO News has reported.

They emphasized that Washington’s vote-by-mail system includes safeguards that ensure only valid, verified ballots are counted.