[Highland Park] Suspicious red truck

Yesterday afternoon I was turning into my block and passed the alleyway directly behind my house.  I saw a large commercial truck slowly making its way through the alley and (looked like casing the area)  I pulled up in front just in time to see them come onto my street I followed them a block or so and took down the license number and reported it to the police.  2 men were in the vehical and it was a large red open bedded truck.  I could not see into the bed as it was higher off the ground and nothing protruded.  With people's copper pipe being stolen and other break in's I thought it was worth reporting. Debi