The 15 year old has been missing from the Ballymagroaty area since around 2 pm on Monday, June 25.
A police spokesperson posted on FSNI Foyle Facebook page: “If you have seen Kevin or can help us locate him please contact 101 and quote police reference number 464 26/6/2018.”
The missing teenager later replied to the post: “BAD PHOTO ER BOYS.”
His post prompted swift responses from both the police and members of Kevin’s family who urged him to return home immediately.
PSNI Foyle said: “Kevin, you need to make contact with Police or with your family as soon as possible. We need to check you are OK.”
A family member wrote: “Kevin u have ur family very worried about u have some respect for ur mammy and granny and get in touch with them.”