cockroaches in the bathroom after putting bug powder
I live in a university accomodation. Some days ago I noticed some ants in the bathroom, but I called the uni and they sent an expert that put some bug powder in the bathroom. This happened two days ago,, and yesterday morning when I woke up I noticed a dead coackroach in the bathroom. What is happening? Is this a sign there's more? I'm deadly afraid of cockroaches, and I don't know if it was a german one. I don't have a picture but it was black, not very big but not very small either. It was maybe a little smaller than my thumb.
For context, the day prior there were some operations on the sewer system. Could be correlated? I already checked the cardboards, I washed everything and used bleach on the floor, but I didn't find more for now, not even poop or eggs. This morning when I woke up there was none, but I don't want to celebrate just yet.