How can I destroy AIs who get away from camera view automatically?

is there any way do detect whether an AI is in camera view or not?

it is a top down scene when my character is running along a street and zombies are following him.

I want to destroy zombies who are passed and are not in camera view but not those who are waiting further.

I need it to be optimized to use for a mobile game.

is it even possible?

any little help?

so I set 10 seconds life span for each zombies and works almost fine as expected :)))

But, what about the zommbies ahead of you .they might get destroyed even before you touch them if your pace is slow.

I spawn them right before coming to camera view and 10 seconds is enough for them. they cannot run fast. their speed is 150 and my character speed is 450

player movement is added automatic on tick event and I only move left and right using gravity motion event to avoid zombies. so speed is always 450 and they never stay there more than 10 seconds