Bitcoin is a safe place to invest, and investors' money is well kept, and there are plenty of wealthy Bitcoin builders, so we do not have to worry about it happening. Fraud or risk of loss, Bitcoin only dangerous when an investor does not have enough knowledge but still engaged in buying and selling.
Honestly there is no such thing as safe place to invest. Every investment have its risk so we can say there is no absolute safety in it. Though with regards to Bitcoin network, it is secure with lots of nodes to confirm the validity of the transaction and huge hashes to maintain the security of the chain.