Police in a city just east of Seattle said Friday that numerous mail ballots have been stolen from people's mailboxes and placed or discarded elsewhere.
The post office alerted the Sammamish Police Department "that unopened or incomplete ballots have been inappropriately placed in out-going mail bins," the city of Sammamish said Friday.
Police have also investigated bags of mail that had ballots in them on roadsides and in ditches.
The postal service delivered roughly 90% of ballots in Sammamish on Thursday, and the discarded mail was found Friday morning when carriers were delivering other packages.
Police are trying to redirect the ballots back to their intended recipients.
The incident is the latest in a string of mishaps with mail ballots as voters try to avoid polling places during the coronavirus pandemic.
Some 112 mail ballots were found in a dumpster this week in Jefferson, Ky.
A postal worker in New Jersey was arrested earlier this month after 1,875 piece of mail, including 99 mail ballots, were found in a dumpster there.
Two postal workers were arrested and accused of throwing away heaps of mail this week in the critical battleground state of Pennsylvania.
Despite these problems, mail ballots appear to be mostly safe and free of fraud. According to the Heritage Foundation, a conservative think tank, only 208 of 1,298 proven instances of voter fraud over the past two decades were related to mail absentee ballots.
The Associated Press contributed to this report.