Theoretically, if Bitcoin was used, it could have been more transparent if they were required to report all the addresses and amounts used, but it would come with a risk of hacking or false hacking. Governments are pretty bad with cyber security, their servers get hacked quite often, now imagine if they used Bitcoin and their not only data, but their funds were also stolen. Another problem is that corrupt government officials could steal the coins and then claim it was a hack. In either scenario, there's zero chance of retrieving coins.
They can always track the transaction in bitcoin and cryptocurrencies as the transactions is transparent in the public ledger, the problem is when the authorities didn't even know what the blockchain is and how to use it. How come could they tract transactions in that way? That is why some government have already hiring blockchain experts to help them with issues regarding these. If government isn't really concern about this new technology, lots and lots of people will just fall to frauds.