Based on the
post from theymos I searched the forum for information about this account. Maybe it really is the person the OP is talking about.
Here is some information I found:
Anyone know what happened to knightmb and his 371,000 BTC?knightmb on bitcointalk - from 371,067.36 BTC to Mitt Romney extortion.https://bitcointalk.org/index.php?topic=6825.msg973679#msg973679If this is indeed the person the OP is looking for, his story ended sadly.
KnightMB, a.k.a. Michael Mancil Brown Dumps Over 370k BTC
According to on-chain data, the total BTC holdings owned by KnightMB have been sold off. A Bitcoiner revealed in a tweet that Brown either spent or donated his total BTC holdings. He also created a so-called Timekoin cryptocurrency project. Brown was later arrested for blackmailing Mitt Romney in exchange for Bitcoin.
KnightMB’s last public hearing was in a 2016 court document detailing a lawsuit against him. The U.S. Department of Justice convicted Brown of six counts of wire fraud and six counts of facilitating interstate commerce to commit extortion.