This lawn is common bermuda.
There is a weed that looks somewhat similar to crabgrass. But I do not think that it is crabgrass. It is darker than the crabgrass in the yard, and also, it does not have the same crown shape at the base that crabgrass does.
I have included three pictures for you -- one far away shot, one medium distance, and one close up.
What is this, and how do I get rid of it?
far away picture
(notice the dark green stuff in the middle of the bermuda)
MEDIUM RANGE PICTURE
CLOSE UP PICTURE