Detectives and forensic police are combing through two homes and a vehicle after an anonymous tip-off into the death of two-year-old Connor Horan at his babysitter's home.

The three crime scenes were declared in Warwick, 73 kilometres south of Toowoomba, on Friday, with investigators appealing for the person who phoned Crime Stoppers to come forward.

The toddler died on Sunday, August 19, 2018, at Warwick Hospital after being brought in with head and internal injuries by his babysitter, who said Connor fell down a small set of stairs.

Connor died two days into the stay with the 38-year-old female babysitter. He was meant to stay with her until the following Sunday.