Police and prosecution load boxes of evidence in a car after conducting a raid on the National Election Commission in Gwacheon, Gyeonggi Province, Thursday. (Yonhap) Two officials of the election authority in Songpa-gu, southern Seoul, are under investigation for not taking necessary measures in the ballot shortage incident during the June 3 local elections, according to a joint investigative team of police and prosecutors on Tuesday.The officials are to be summoned for questioning later in the day on abandonment of duties, as investigators believe they had reason to anticipate the shortage of voting papers and did nothing to prevent it. They are also suspected of receiving reports of ballot shortages from voting stations and ignoring them.Multiple polling stations across the country had shortages of ballots during the election in early June, resulting in delayed voting, deprivation of voting rights and nationwide furor and protests at ballot counting stations in Seoul.President Lee Jae Myung ordered a thorough investigation into the incident, leading to the joint investigative body based in the Seoul Central District Prosecutor's Office.Investigators found a number of potential issues in the election, including the same serial number being found on two ballots. There was also evidence that election officials rigged voter counts to hide previous mistakes, without going through the official process.The investigative team on Tuesday will also question two members of the National Election Commission related to charges faced by Roh Tae-ak, who has been accused of accompanying his spouse on three overseas trips during his tenure as the chief of the NEC. Roh resigned last month to take responsibility for the ballot shortage fiasco.