SCAT - need help to ID (Pics)

[MDCAT]

Some critter has been leaving its scat on our carport every night for the past year.  Can't figure out what's doing this.  The critter only comes at night and does this.  The poo is as big around as a cigarette butt and about one-half to three-quarters of a inch long.  Could it be a chipmunk, a field rat?  We don't know.  Tired of stepping in this stuff.  Please give me your input, need help to exterminate this varmint.  Click on pictures to enlarge.
Thanks,
Mike

[Dixie Dude]

Set a trap (rat size) using peanut butter on the trigger.  Could very well be a chipmonk or rat.  Might be a small possum or racoon.  If the critter is larger than a rat or chipmonk, it will come out of the rat trap.  Then set a bigger trap.  I looked again, and it almost looks too large for a rat or chipmonk, but it could be.