The biggest crime didn't happen yet. It will be once we let the central banks controlling the Bitcoin network. But if not, I think that it is MtGox that holds the record in the media. In term of funds for sure, all these shit ICOs are the biggest. Still, it's minimal compared to other currencies and like the currencies, Bitcoin can't be blamed but the platform people use and so these people themselves.
Just a few hacks I collected quickly from the web, as you see, only exchanges here...
Mt. Gox 850,000
BTC Bitfinex 120,000
BTCBitcoinica 101,000
BTCAllinvain 25,000
BTCBitfloor 24,000
BTCBitstamp 19,000
BTCCryptsy 313,000 LTC
Poloniex 97
BTChttps://bitcointalk.org/index.php?topic=16457.0https://en.wikipedia.org/wiki/Bitfinex_hackhttps://www.hackread.com/cryptsy-hacked-bitcoin-worth-usd-6-million-stolen/https://www.cnet.com/news/bitcoin-exchange-bitfloor-shuttered-after-virtual-heist/https://en.wikipedia.org/wiki/Mt._Goxhttps://en.bitcoinwiki.org/wiki/Value_overflow_incidenthttps://en.wikipedia.org/wiki/Bitfinex_hackhttps://en.wikipedia.org/wiki/Bitstamphttps://www.coindesk.com/bitcoin-bitfinex-hack-multi-sighttps://www.coinbureau.com/analysis/biggest-bitcoin-hacks/