Eleven cats were left to die after being dumped on a street in east London in sealed cardboard boxes.
They were spotted in Stratford by a passer-by who heard the cats miaowing.
The cats would have suffocated after a couple of hours if they hadn't been found, according to charity the Celia Hammond Animal Trust.
Anyone with information can contact the Celia Hammond Trust in confidence via email on firstname.lastname@example.org or call 020 7474 8811.
The charity says the owner may have other cats they may not want.