So you find someone unscrupulous enough to kill your honey bee colony. Problem sorted, yes? Actually NO! Here's some of the many reasons that killing a colony is a fools choice.
A living colony of honey bees is like a well run city. Some bees remove rubbish, some defend it from other pests, some repair the comb holding litres of honey. When a colony is destroyed, there are no bees to carry out these essential jobs.
Tens of thousands of dead bees will start to smell. This pungent smell of death will soon start to attract other pests. These will include flies, beetles, mice, squirrels, rats, and millions of other tiny pests, including bacteria, fungi etc.
Then there is re-infestation by another honey bee swarm. Honey bees can smell unguarded honey from 2-3 miles away. (When we remove a colony we remove all the honey.) When a scout bee smells your honey, 10-50 thousand bees will turn up on mass. Depending on the type and strength of the poison/insecticide you originally used will depend on what happens to the new swarm that turns up. But, you think a honey bee swarm is scary, imagine one that's half poisoned with insecticide! Rather you than me!!
A third of a honey bee colony is out foraging, a third are nursery bees (they look after the hive while they grow up) and another third is unhatched grubs about to emerge. The illegal insecticide you chose will depend on which third of the population you kill. Some will kill all the nursery bees, but not the foraging workers. None will kill the young bees about to emerge from the wax.
Without adults and nursery bees to guide the newly hatching bees, (don't forget a Queen can lay 2000 eggs a day, and these take 2 weeks to hatch out, so you do the maths) the young bees will search for light. In a natural setting, this would be sunlight at the hive entrance, but in a dead hive, if the bees hatch at night, they will start to follow any light they can find. Quite often gaps around loft hatches, light fittings in bedrooms and bathrooms etc. A lovely thing to wake up to every night for a fortnight!
So lets break things down for you -
Killing bees is nearly always illegal
Killing bees is cruel
Killing bees is terrible for the environment
It can lead to lots and lots of other pest problems
It rarely gets rid of the bees for long
Your home will smell of death
Your home will attract other swarms