Thank you!! This is what we did both days and haven’t and probably won’t say anything. We have both been in urban education (teachers now instructional support//admin) and I’ve never had to deal with this before.

Thank God we only have 4 more days!

In first grade, I wouldn't explain anything to him. Book "appointments" those days such as hair cuts and use those as the reason he's not in school. You won't be the only parent doing this. There's a chance he'll hear about the threats from older kids but summer is coming up and he probably won't remember by the time school starts up again in Fall.
For older kids, I'd also keep them home. It's unlikely the threats will materialize but those days are stressful and personally I've never regretted erring on the side of caution when it came to my own children.
- Parent and teacher who is absolutely sick of this crap

My son’s school (NOT in the DMV area) has had three threats of school violence in the past 3 weeks. We have opted to keep him home the two specific dates violence was threatened. We have simply told him he won’t be going to school those days.

How do you or have you (or would you) explain to your child? He’s in first grade. We go to an otherwise outstanding school.