James told The Times a local resident found approximately seven tax statements in the area and brought them back to the Treasurer's Office.
James said the local resident found the statements off the side of a road.
"I have contacted these people," James said. "I'm just afraid there might be several more. These are just the ones (the local resident) found. There could be more than this that were removed and weren't found. I'm worried there may have been a lot more."
James said she has contacted the Clay County Sheriff's Department regarding the issue, in addition to the Brazil City Post Office.
Clay County Sheriff Mike Heaton said the person that discovered the property tax statements found them near Seelyville in Vigo County. All of the statements, however, were for Clay County residents.
Heaton said the case is under investigation, adding that theft of mail is a class D felony punishable with up to three years in prison.
He said there were several unknown variables involved in the investigation, including officials did not know if the pieces of mail had been opened or if other mail was missing.
"We're dealing with a lot of unknowns at this time," Heaton said.
He added theft of mail has taken place in Clay County in the past.
"We've had cases where people were stealing (mail), but nothing recently," he said. "We've had stolen mail before, but these particular things all dumped, tax statements, it's an oddity."
Heaton said CCSD had contacted the Vigo County Sheriff's Department to see if there had been other recent investigations into mail theft in the area.
Those who have not received tax statements should contact James at 448-9009 and a new statement will be mailed out.