A 14 month-old girl from the Sandringham Drive area of Sutton-On-Sea was taken to hospital in Grimsby, suffering from a suspected brain injury on July 28.
She was transferred to Sheffield Children's Hospital where she died from her injuries.
A 30 year-old local man has been arrested on suspicion of murder and is currently being interviewed at Skegness Police Station, Lincolnshire Police said.
More top news
Weekend weather update: Fine start. Becoming wet and windy. Colder next week.
Residents who fear fracking could blight a north Derbyshire village marched through nearby streets today.
Bradford is one of the most affordable cities to buy a house in the country, a report has found.