civil suit

okay.. im in colorado so im really worried. im at work this morning and i get a call from my dad who lives in another state. he tells me someone is looking for me and they have a civil case number. he gives me the number and case number. i goto my states website and type in the case number nothing pops. i goto my dads state and nothing pops up. i guess my question is HOW do i find out what this is? who issued it? why? im unaware of doing anything worthy of being sued! HELP