Miami-Dade corruption prosecutors are investigating allegations that at least 275 ineligible felons voted illegally in the county’s November 2016 general election.

The questionable ballots were discovered during an examination of a sample of 922 registered, but ineligible felon voters identified and purged by the Miami-Dade Supervisor of Elections Office in the six months after the 2016 election. It is a third-degree felony to cast a fraudulent vote or to swear falsely when registering to vote.

The investigation’s existence was disclosed in a July 25 email from prosecutors to Andrew Ladanowski, a Coral Springs data analyst who contacted authorities after his public records request to the elections office turned up evidence of voting by ineligible felons whose civil rights had not been restored.

“As my unit chief, Tim VanderGiesen, has informed you, I have been assigned as the lead attorney for this investigation,” wrote Miami-Dade Assistant State Attorney Kerrie Crockett.