From wikipedia:
Mark Marie Robert Karpelès (born June 1, 1985), also sometimes known by his online alias MagicalTux, was the CEO of bitcoin exchange Mt. Gox. He moved to Japan in 2009.
Karpelès was born in 1985 in Chenôve, France, the child of Anne-Robert Karpelès, a geologist. He was raised in Dijon. Between 1995 and 2000, Karpelès was educated at Collège Prieuré de Binson in Châtillon-sur-Marne, near Dormans. He then spent one year at Lycée Claude Bernard in Paris, before completing his education in 2003 at Lycée Louis Armand in Paris.
According to Karpelès' LinkedIn page, he worked from 2003 to 2005 at Linux Cyberjoueurs as a software developer and network administrator. Karpelès is a PHP developer, and has contributed to the language's official repository of extensions with proctitle, which allows the name of the current process to be changed on Linux systems, as well as developing a fully functional DNS server and an inetd, also both in PHP.
From 2002 to 2005 Karpelès was involved in the Ragnarok Online community, hosting and administering a private server (French Ragnarok Online, shortened as fRO, mimicking the official kRO, jRO and eRO naming). During this time he particiapted in the development of the Ragnarok Online server emulators Freya and then Nezumi. Before becoming a fork of Freya, Nezumi initially started as a clean-room PHP implementation of the server part of the game, aiming at improving performance, stability, portability, and resource use notably compared to the then current eAthena and jAthena servers, as well as making the hosting of such servers legal instead of using leaked AEGIS server builds. Karpelès tried to bootstrap a hosting organisation named Ookoo (then pivoting into ff.st) which also served to host the private server community and development resources (such as the homepage, forums, IRC, SVN, and bug tracker). ookoo.org and ff.st would later fall under Tibanne's umbrella until each domain expired.
Karpelès founded Tibanne Co. Ltd. in 2009. He is CEO. He was a founding member of the Bitcoin Foundation, created in 2012 with a mission to standardize and promote bitcoin, and served on its board until February 2014.
Karpelès acquired 88% of the Tokyo-based company Mt. Gox from programmer Jed McCaleb in 2011. Mt. Gox filed for bankruptcy in Japan on February 28, 2014 and for Chapter 15, Title 11, United States Code bankruptcy in the United States (Texas) in March 2014.
Karpelès was subpoenaed by the United States Department of the Treasury's Financial Crimes Enforcement Network to appear in Washington, D.C. to provide testimony on April 18, 2014. Karpelès, in a court filing by Mt. Gox lawyers, responded that he did not have a lawyer for this matter and therefore declined to appear. Karpelès sought to appear in D.C. to testify on May 5, 2014.
According to a joint report by Cyrus Farivar of Ars Technica and Pierre Alonso of Le Monde, Karpelès was found guilty of fraud when he was tried in absentia in France in 2010. He also admitted to having "pirated" a server to French authorities. He was sentenced to a year in jail but has not yet served his sentence.
Ross William Ulbricht, while on trial for operating the undercover Silk Road marketplace, claimed in 2015 that the pseudonymous "Dread Pirate Roberts" behind Silk Road was not him but Mark Karpelès. Karpelès publicly denied the claim on Twitter, and Ulbricht was eventually found guilty.
Karpelès was arrested on 1 August 2015 by Japanese police on suspicion of having accessed the exchange's computer system to falsify data on its outstanding balance, he was re-arrested and allegedly charged with embezzlement.
Karpelès was released on bail in July 2016, but must remain in Japan.