dhs? what

i was at wrork hubby was in bex son was asleep dhs left a card in our door im dumb founded what could this be? now we had tentants and their kids played in the front yard and 2 of her other kids r in foster care and another kid was taken away from her could it be for them im a teacher and would never harm any child exspecially mine ???? confused my son is almost 6 and is very welled cared for from me and his dad