What is the ruling on killing flies with adhesive tape while they remain alive?

The ruling on killing flies has been previously explained. As for killing them with sticky tape: if it kills them immediately, there is no harm, and it may be better than harmful pesticides. However, if the killing is slow, it is obligatory to promptly kill the accumulated flies, or to seek another method, because slow killing contradicts the Islamic command to kill humanely, as stated in the Hadith narrated by Muslim: "Indeed, Allah has prescribed excellence in everything. So, if you kill, then kill well." It has been narrated from Sheikh Al-Uthaymeen, in his commentary on Riyad al-Salihin, that if a person wishes to kill a mouse (which is permissible to kill), he should kill it humanely and with a method that takes its life immediately, and not harm it by leaving it to die of hunger and thirst on the sticky tape without follow-up.