The dog was named after another dog named Killer, which was owned by Earnhardt Jr.’s father.
Earnhardt and Killer were part of Greg Biffle’s pet calendar last year.
Killer also was beloved by Earnhardt’s fans.
Sad for all of us that loved this dog so much. #RIPKiller. He was as special as can be. pic.twitter.com/q7eg0upIOM
Former teammate and fellow dog lover Danica Patrick tweeted her condolences.
