He found the cat as a stray. The landlord stole the cat and gave it to his girlfriend and had her take it to a shelter.
Older cats are often kept in shelters for less then a week before they are put down.
But in this case they scanned it and discovered that it was chipped. So Frank lived and was returned to his proper home.
But there is a level of malice here that is quite amazing. You steal someone's pet and send it to it's probable death?
Who said he found the cat as a stray? Why it was the same person who claimed he owned it. What a coincidence. I had a dog stolen - lifted right out of my back yard. When it was recovered (because fortunately someone saw who took it) the thief claimed he didn’t know it belonged to anyone. Ie a stray.