Tor sees use by many important segments of the population, including whistle blowers, journalists, Chinese dissidents skirting the Great Firewall and oppressive censorship, abuse victims, stalker targets, the US military, and law enforcement, just to name a few. While Tor is not designed for malicious computer users, it is true that they can use the network for malicious ends. In reality however, the actual amount of abuse is quite low. This is largely because criminals and hackers have significantly better access to privacy and anonymity than do the regular users whom they prey upon. Criminals can and do build, sell, and trade far larger and more powerful networks than Tor on a daily basis. Thus, in the mind of this operator, the social need for easily accessible censorship-resistant private, anonymous communication trumps the risk of unskilled bad actors, who are almost always more easily uncovered by traditional police work than by extensive monitoring and surveillance anyway.
In terms of applicable law, the best way to understand Tor is to consider it a network of routers operating as common carriers, much like the Internet backbone. However, unlike the Internet backbone routers, Tor routers explicitly do not contain identifiable routing information about the source of a packet, and no single Tor node can determine both the origin and destination of a given transmission.
As such, there is little the operator of this router can do to help you track the connection further. This router maintains no logs of any of the Tor traffic, so there is little that can be done to trace either legitimate or illegitimate traffic (or to filter one from the other). Attempts to seize this router will accomplish nothing.