A woman has testified to having provided sexual services to a high-ranking official in connection with a snowballing sex scandal involving several figures in the upper tier of society, police said Thursday. As part of a preliminary investigation, police have been looking into suspicions that a 52-year-old construction contractor, only identified by his surname Yoon, hired some 10 women to perform sexual services for five to six people, including former and incumbent high-ranking government officials and other figures, such as the head of a hospital, in return for business favors. Media reports have also been circulating that there is video footage of intimate rendezvous between the figures and the women at a luxury vacation home in Wonju, 132 kilometers east of Seoul, which is allegedly owned by Yoon. \"We secured a testimony that the woman had provided sexual services to a high-ranking official (whose identity has been withheld) at Yoon\'s vacation home in Wonju,\" a police officer said, adding that it has now become a full-fledged investigation. As for the video footage, police said they are analyzing a video file provided by the woman, but cannot confirm its contents. Police also said they have asked the justice ministry to ban Yoon and two other people, including his nephew, from leaving the country. Meanwhile, police said they have secured circumstantial evidence that Yoon allegedly committed illegal acts while trying to win a construction contract and plan to summon him for questioning. Police said they will further investigate whether the figures, who allegedly received sexual services, peddled their influence for Yoon. Other women, including a house wife and an artist who were allegedly mobilized for the crime, are also expected to be summoned by police for questioning, they said. Meanwhile, Huh Joon-young, a former police chief who is rumored to be allegedly related to the widening scandal, flatly denied his implication. \"There are reports circulating that Huh Joon-young was involved in the scandal, which is a slander,\" the 61-year-old former commissioner of the National Police Agency tweeted on his account, referring to himself in the third person. Huh added that he would stab himself to death if he were found to have been implicated in the sex scandal.