might be meths, that is purple and smelly, goes bang well too. I the woodentops think of it they could ask all outlets that sell it nearby who the killer is, dont suppose they will though!!
I saw the “purple liquid” and instantly thought of PVC pipe primer. Nasty stuff, chock full of MEK. Burns like a sumbitch and the vapors can knock you over. Put a gallon through the letterbox and toss in a match. BOOM. Heck you wouldn’t even need to light it off. Just the fumes would kill anyone in the house.
And the good news is that anybody can buy it, by the gallon if you want, at just about any hardware store.