The "Bitcoin Savings & Trust" operated by a BitcoinTalk user known as pirateat40 (Trendon Shavers) shuts down after collecting an estimated 700,000 BTC from investors by promising 7% weekly returns. It was Bitcoin's first major Ponzi scheme and a harsh early lesson for the community about counterparty risk and the age-old adage: not your keys, not your coins. Shavers was eventually charged by the SEC and sentenced to 18 months in federal prison in 2016.
Wikipedia: Trendon Shavers