A man has been arrested on suspicion of murdering a one-year-old boy.
The toddler was found with head injuries at a house in Speke, Liverpool, on Friday evening. He was taken to hospital but did not survive.
Officers were called to the address in Belsford Way by the ambulance service at about 18:00 BST, Merseyside Police said.
A 23-year-old man from Winsford, Cheshire, remains in police custody where he is being questioned.
A post-mortem examination was due to take place on Sunday, the force added.