It's an inmate from Washington state corrections. They might be calling you because they have the wrong number! They can't hear anything on the other end so that's probably why they are trying to call multiple times. Just listen to the recording g it gives you an option to block future calls of this nature.
I just got a call from this number (360 532 9667) which the caller ID labeled "Inmate Phone". I get calls from telemarketers and scammers all day, every day, yet this is the first time I've seen this particular one. The phone rang forever before it finally quit.