Who called from 9255559851

Another scam call. Caller ID "California Call".

Caller ID said it was Dir Asst  CA.  They left no message on the answering machine.

I get calls from this number or from (925) 439‑878‍7 almost every day - there is no one there and when I return the call it says it is not a working number.

So glad I have Caller ID.  I do not pick up calls from an unrecognized number or name.  If it is a legitimate call, they will leave a message.  I've found many of these calls are from legitimate number that are "no longer in service" with various phone systems.  My question is:  how are these people getting these numbers?

phone spoofing explanation
http://en.wikipedia.org/wiki/Spoofing_attack
http://www.fcc.gov/guides/caller-id-and-spoofing