There's nowhere to legally buy grenades in the US. They clearly bought at least those illegally, so why not their guns, too?

You could get them from the same people who sold weed or coke. I think people underestimate how much of a straight-out black market there is for guns.

You are hitting all the usual NRA talking points. But there was an actual study done once that examined the black market for guns in Chicago, and found that, contrary to what the NRA always says, underground markets are "thin" and "transaction costs are considerable".

It proves that we need tighter trafficking laws to reduce the amount of guns that get diverted to criminal markets.

We need that much more than more laws that also go unenforced like the ones we have now (tens of thousands of illegal attempts to buy guns annually... law enforcement follows up on a dozen or so).

I'd bet the exact opposite: all guns bought illegally.

they need to find WHERE this was bought from, and the person/manufacturer should be held accountable.

Not impossible, but very difficult.

so I'd think smaller bombs could be made. Perhaps not technically "grenades", but I think it would be understandable if the correct terminology wasn't used.

Bought on the Internet or gun shows?

I was under the impression that they were lobbing 'loaded' pressure cookers...

watched that. The grenades I heard about...supposedly "a bag of grenades". But the guns were certainly real.

is a good guy with a pressure cooker

The NRA is in charge

Has been all week.