This caller has been calling for the past 2 days.  When my voicemail picks up they must listen to my voicemail message and hang up.  They just stay on long enough that it records noise in the background which sounds as if they are in a car on their cell phone.  If I don't know the phone number I do not pick up, because 9 out of 10 times it is a telemarketer for a charity.

calling several times a day

I answer the phone, no one there.

The number comes up on my landline caller id as "Local Call Back". I thought that a Google search would reveal someone I knew or a business that I was thinking of doing business with; however, it appears that it is just another annoying telemarketer that shouldn't be calling me.

Called at 7:40 PM.  I let the answering machine pick up all calls after 6:00 because usually it is someone asking for money that I don't have.  They did not leave a message so I don't know what they wanted.