Even serial killers can't hurt animals

I have had the craving to write limericks for ages then my fingers typed these... enjoy?

There once was a girl who loved lace,
then she disappeared with no trace.
they found her head
at the foot of my bed,
now no more they praise her grace.

Once a man who liked the dark
got startled once in the park,
Jammed my knife in his spine
then laughed at his whine,
serves him right for his vulgar remark.

There was once a woman cried
she made no attempt to hide
So I killed her quick
hit her with a brick
She'd have lived if she didn't lie

There was a dog who peed on my leg.
he then had the nerve to beg,
I shooed him away
yet another stray
the only one I didn't want dead.