@Lal and others who may be interested
First of all thanks for the reply.
I read the story of Alavaka Yakkha (Yaksha) in a book about Jayamangala gatha, which is commonly recited by monks in my place.
When searching internet I found two references to Jayamangala gatha (eight verses, hence known as atthagatha or asthagatha) and Alavaka Yakkha, here are they: http://www.aimwell.org/Jayamangala%20Gatha.pdf
and http://www.aimwell.org/Jayamangala%20Gatha.pdf
Both these stories say Alvaka Yakkha was ferocious and Buddha subdued him.
Hope the above links can make you familiar with the story. If Catumaharajika Yakkhas are (some of them) capable of killing and they live in close proximity with humans, one should be aware of this possibility.
May blessing of Triple Gem be with us always.