Japanese police and government ministries began gathering information about Mt. Gox following its closure this week.
"I am getting to feel that this whole case might have been well planned so that prosecutions of any kind are made difficult," Saito said.
Mt. Gox received a subpoena this month from U.S. federal prosecutors in New York asking it to preserve certain documents, The Wall Street Journal reported this week, citing an anonymous source familiar with the matter. A spokeswoman at the U.S. Attorney's Office for the Southern District of New York declined to comment.
The fall of Mt. Gox is one of the biggest blows to bitcoin, a digital currency often billed by proponents as being free from government regulation and costing nothing to send and receive.
It follows the theft last November of over $1 million in bitcoin from Bitcoin Internet Payment Services, a Denmark-based exchange that promoted itself as Europe's biggest, as well as a heist involving about $1.4 million from online wallet service Inputs.io, and the disappearance of a Chinese bitcoin exchange with more than $4 million in it.
Bitcoin was trading hands at $556 following the bankruptcy announcement, down slightly from the day's high of $579, according to CoinDesk.com.