Folks,

Some internet user, operating from a Comcast node in Oregon St, USA,
has turned nefarious, enjoyed identity theft, acted with impunity, and
carried on a tone of smug insolence. Given his IP addr/host node, and
having an open IRC communications, is there a way to discover his true
identity? It's been going on for quite some time (years). I could set
up a web service and have him click a link, but are there other
vectors? I am doubtful appealing to authorities will provide any
meaningful resolution.

Thanks