There was actually blood on the bag and camera - they had broken out my step-dad's rear window in his F150 before they tried mine, but it wasn't his camera they left sitting there. I figured they cut themselves on some broken window glass beforehand. When the cops got there they said they had gone up and down the road and in the hotel parking lot across the street and had broken into 10 or 12 other vehicles... I guess mine was the first with an alarm and it scared them enough they dropped the stuff and took off.
Sad thing is, I never heard my alarm going off, found all this the next morning when I hit my alarm disarm and it chirped 4x at me instead of the usual 2, prompting me to walk around and saw the little bag sitting on my bumper, then noticed they'd scratched hell out of my back window smashing it with the piece of broken concrete - it was dropped next to the back of my truck and also had blood on it. Then I saw they had shattered the F150's back glass and looked like they had gone through it, I think all they got was some change out of the ashtray.
Never did find out if they caught them (doubt it), but it did prompt me to have my alarm changed out for a 2-way paging alarm, put those in all my vehicles now.