Police are investigating a polling station staff member they suspect of casting a ballot on behalf of her husband in Seoul’s Gangnam area on the first day of early voting ahead of Tuesday’s presidential election.

Police in Gangnam’s Suseo neighborhood said Friday that they arrested the election clerk without a warrant the previous day on suspicion of voter impersonation.

The clerk is accused of voting on behalf of her husband around noon on Thursday and then casting her own ballot five hours later. 

Police say they made the arrest after an observer spotted her voting twice. 

The clerk is said to have admitted to the crime under police questioning but made no statement about her motive. 

The clerk, who is a contract public servant at the Gangnam Public Health Center, was found to be tasked with issuing ballots to voters after checking their identification during the two-day early voting period. 

Gangnam District removed the clerk from her contract position on Friday. 

The National Election Commission removed the clerk from her polling staff duties on Friday and filed a police complaint against her while asking the police to also investigate her husband.