Election officials have opened an investigation into whether the wife of potential U.S. Senate candidate Herschel Walker cast an illegal ballot when she voted in Georgia’s presidential race last fall from her home in Texas.

The investigation will look into allegations that Julie Blanchard violated state election laws requiring voters to be Georgia residents, according to a case sheet The Atlanta Journal-Constitution obtained Friday. Blanchard, who returned an absentee ballot from her Texas address, owns property in both states.

The inquiry could undermine Walker’s stance against voting fraud if he enters the race as a Republican against Democratic U.S. Sen. Raphael Warnock. Walker is a former University of Georgia football star who currently lives in Texas.

Walker has called for prosecutions of voter fraud, though there’s no evidence of rampant abuse. He has also echoed former President Donald Trump’s false claims of voting irregularities, and Trump has encouraged him to enter the race.

Republican Secretary of State Brad Raffensperger approved launching the investigation, according to the secretary of state’s office.

“It is standard practice for the secretary of state’s office to open an initial investigation into all complaints,” Deputy Secretary of State Jordan Fuchs said. “This is a policy the secretary put in place upon taking office.”

Election records show that Blanchard mailed an absentee ballot in October from the couple’s residence in Westlake, Texas. Blanchard also owns a home near Buckhead in Fulton County.

Blanchard and Walker receive a homestead exemption — a property tax break given to homeowners on their primary residence — on a Texas home that the couple purchased in 2011, according to property records. Blanchard doesn’t claim a homestead exemption on her Fulton property. A homestead exemption is one of the criteria set in Georgia law to determine residency.

State law determines residency based on where a voter’s “habitation is fixed,” and those who move to another state with the intention of making it their residence lose their eligibility to vote in Georgia.

Blanchard has said she considers herself a resident of Georgia, where she has a driver’s license, owns a car and does business.

Before last year’s election, Blanchard hadn’t voted in Georgia since 2008. Her Georgia voter registration was canceled in 2017 because of inactivity, and she re-registered in 2019. Blanchard isn’t registered to vote in Texas.

Election investigations can take months or years to resolve. Cases are then brought to the State Election Board, which has the power to levy fines or refer cases for prosecution.

The questionable vote has already become fodder on the campaign trail.

Agriculture Commissioner Gary Black, the best known Republican in the race, said last week that an investigation into Walker’s wife could complicate GOP efforts to brand the party as champions of voter integrity in a 2022 race.

“I’d say the lights are shining bright on the political playing field now,” Black said of Walker after a recent campaign event in Cobb County. “It makes it very difficult to talk about voter fraud after that. I’m concerned about that.”