Caspa wore a collar but wasn't microchipped. Kerr put posts on Facebook and asked around for news of her missing cat, but was unable to track him down.
He was "super friendly", so she hoped he was at least safe with a new family.
Kerr continued to post on missing pet pages, however, and yesterday was tagged in a Facebook post about a cat that had been found. It turned out to be Caspa.
"I contacted the lady. [She] said that they had him since the last school holidays and they'd been trying to figure out who he belonged to."
"I absolutely can't believe it," Kerr said.
Caspa was in good health when he came home, and Kerr believes he spent his time moving from house to house and being taken care of by different families.
One family told Kerr they cared for him for a while and took him to the vet when he developed an abscess.
Kerr has an 8-year-old daughter who will be coming home from her father's house soon, who would be "over the moon" to see Caspa, who has been in the family since before she was born.
Kerr was unsure how long to keep Caspa inside now he was home, given a month wasn't long enough last time, but said she has already booked him in to get microchipped.