Rural development expert Sombath Somphone has been unaccounted for since December 2012 and the Lao government has not been forthcoming about his case.
Informal lotteries will be restricted or banned, and participation in foreign lotteries forbidden.
The state-run company plans to turn the center into a for-profit tourist attraction in Sayaboury province.
Investigators may be delaying to avoid implicating a provincial governor and his family.
Witnesses said 10 men abducted Ko Tee from his house in Vientiane.
Authorities apprehend 12 residents of Yeub village for cutting down trees on land granted to a Vietnamese rubber company.