I found something like that (translated)

In the mid-1990s, he joined the hackers CCC and THC. They have interfered, among other things, with the governments of different countries and the world's largest corporations and obtained credit card numbers from which they stole money. At the end of the 1990s, Dotcom - then Schmitz - began working with the police and injecting their fellow hackers in turn. Therefore, he got a low sentence for this activity - 6 months.