Insect and Spider Identification: HUGE UGLY Devil Flies..., 1 by jc4l

jc4l wrote:
Hello Friends,

I live in Southern California, and for the past 2 days my condo has been swarming with HUGE \'House Flies\' [If you want to call them that.], I have never seen such gigantic flies in my life. I keep swatting them, opening the screen door and swooshing them out -- back outside. They keep coming back even though all my windows, screens, and doors are kept closed... I do not know what to do. I am a very clean person, I do not leave any food out and I make sure to take the garbage out before it starts to get stinky. This is the first time I have had such a huge problem like this. Where are they coming from? What is attracting them? The only recent plausible things that may attract them are:

A. I recently planted some plants, herbs, and vegetables in pots and in the soil using Target Brand Potting-Mix without fertilizer.
Or,
B. They are hatching and growing somewhere inside my home!

Please help me I.D. this type of Fly. Again, I have never seen flies this large in my life... In the meantime what should I do to prevent them and also find out where they are hatching or flying in from?

Thank you. :)

Sincerely,

John

PS: Attached are Pictures of a single Large Fly with Measurements and a little detail/comparison/scale.