In a roundabout way you can
Go here:
http://www.arin.net/whois/ and put the offending ip into the "search for" box. That will tell you who owns the netblock of the offending ip - but if it was anyone worth their salt they would never launch an attack from their home box; most likely it was from a compromised pc somewhere.
You got the logs from the firewall? Send them to the offender's ISP - you should get a contact from the whois search - at least that may prevent the compromised pc from attacking others for the moment.
Hope this helps some
/JD