Reward,Hadith

Assalamu-alaikum,

I would like to know the Islamic rullings on ‘House Gecko’ (maybe Chipkali in Urdu). I heard from a source that “Killing Gecko is not only permissible but also an act of getting reward (Sawab)”. Is that true? If so, than what is the Wisdom (hikmaat) behind it? Is there any true stories regarding Gecko with prophet Ibrahim (AS) and Rasulullah (pbuh) ? Please explain with authentic quotations from Quran/Hadith/Reliable Fiqh books.

Zazakallahu khairan,