That does not rule out previous gas leaks in the home now scattered in pieces.
It probably was a gas leak.
It just seems to be taking a while to reach that conclusion at the scene.
Normally, I’d expect there to be gas leaks after the explosion, even if there weren’t any before, since some pipes are blown apart now, and fittings are gone, etc. At least until the utility crews can turn off the gas further back down the line.
If you didn’t smell gas before, I’d expect you to smell it shortly after.
As I said earlier, there was a tiny gas leak in a fairly large building where I work, and the smell was obvious. There was no doubt we had a gas leak, the only question was where it was coming from, and a sniffer found the source pretty easily.