STARR COUNTY- More than 200 registered voters received letters this week, asking them to prove their citizenship.

It's part of an on-going investigation into potential voter fraud by the Texas Secretary of State.

The Secretary of State has worked alongside DPS to match voter registration records.

Around 95,000 people identified as non-citizens were found on voting lists.

Residents who receive a letter in the mail will have to prove citizenship within 30 days.

Otherwise, voter registration will be cancelled.

Starr County Elections Administrator, John Rodriguez says out of the 211 letters sent out, around 25 have responded.