When you mentioned asps, I started to think of Cleopatra.
Did she use them as a murder weapon?
I heard about a garter snake who was offered a part in a Cleopatra movie but he turned it down because he didn’t want to make an asp of himself.
The story is cleopatra used asps to commit suicide, not murder. She had them smuggled in a jar or dates or something.
The poison is (apparently) quite painless, a neurotoxin, and you just go to sleep and don’t wake up. So it has been a pretty common method of suicide back home for 4000 years.
The main issue with the story is an “asp” is more properly known as the Egyptian cobra, and it’s a big black snake that quickly grows to 1.5 meters. So it’s unlikely to be able to be smuggled in a jar of any kind.
That said you could probably get several juveniles and get the job done.