I have a massive problem with outdoor cats... Filthy agressive predatory introduced species that kill and consume native wildlife on a scale that commercial land developers can't even begin to compare to. The fact that they reek and urinate all over everything certainly doesn't help endear them to me either.
Frankly outdoor cats are a threat and, like any wildlife threat that is in an area it doesn't belong in, it should be dealt with accordingly. I wouldn't suggest poison, as there's no need to go out of the way to be cruel or create suffering (not the individual animal's fault it was let loose to terrorize local wildlife and humans alike) plus the potential contamination of something other than your target is too great a risk... But by all means trap or shoot (if you're a good shot and can take them down cleanly) every wretched mongrel stray (If it's outdoors, it's a mongrel stray) you encounter. Any trapped, take them to the pound where they can be euthanized.
Out of every species which ended up introduced someplace it didn't belong... brown tree snakes, cane toads, rabbits, rats and the monitors and burms infesting the everglades these days... Cats are by FAR the most destructive and dangerous species and any damn fool who allows their animal outside (I understand this case was an accidental release, but just who's responsibility is it to keep the animal contained?) deserves to lose their pet. Once it's not under human control, it's no longer a pet, it's an invasive species and should be dealt with accordingly.
"Genes, Like Leibnitz's monads, have no windows; the higher properties of life are emergent... And once assembled, organisms have no windows." - Edward Wilson, Sociobiology