Police have raided a regional office of the Korea Land and Housing Corporation(LH) in their investigation into alleged property speculation by the state-run corporation's employees.

The Jeonbuk Provincial Police Agency on Monday sent more than a dozen investigators to three locations, including LH's regional headquarters in North Jeolla Province, to obtain relevant evidence.

The LH's provincial office is suspected of being the origin of a confidential information leak, as many of the 15 current and former employees facing accusations had worked there in the past.

Some 40 people, including neighbors of the workers, were found to have purchased land near government-planned development areas in Gwangmyeong, Gyeonggi Province.

The Gyeonggi Nambu Provincial Police Agency, which questioned three LH employees on Friday, summoned two more as of Monday morning to grill them on whether they had accessed classified information for speculative purchases.

The police plan to complete questioning all 15 within the week, before reviewing arrest warrants for the suspects.