The Raveness of rope and arsenic

Sung after the noose made its killing for slaughter is not
absent of laughter. The killing of a murderer put to death,
for the slaying of her children and husband's hereafter.
The English heart habitual of the cold, arsenic poisoning
and insurance could present a finer life, for this wretched
black widow who was once a loveless wife.
Persuasive emotion soon lost its effect as the hour soon saw
this Venus flytrap was sentenced to death. Daemons
reserved demeanour asserts innocence and petitions did fail
when presented to the home secretary to no avail.
They sung the words never forgotten in fact the opposite
effect for the rhyme gave life through history to this Mary
Ann Cotton.
Yes, Mary Ann Cotton,
she's dead and forgotten
lying in bed with her eyes wide open
Sing, sing.
What should I sing?
Mary Ann Cotton is tied up with string
Where? Where?
She's up in the air and sellin' black puddin' a penny a pair.