By Navtej Johal and Christy Cooney
BBC News
The sister of two-year-old Bronson Battersby has said she does not blame social services for his death.
Bronson, whose body was found in a Skegness property on 9 January, is believed to have starved to death after his dad suffered a fatal heart attack.
Melanie Battersby told the BBC she believed "social services and the police did what they could within the powers that they had".
Lincolnshire County Council has said a "rapid review" will be carried out.
The Independent Office for Police Conduct (IOPC) is also investigating whether there were "missed opportunities" to check on the pair.
Kenneth Battersby, 60, who looked after Bronson full time, was in poor health and had suffered another heart attack a few months before his death, his daughter told the BBC.
The council has said that a social worker called at the property for a scheduled visit on 2 January and, after getting no response at the door, spoke to her manager and the police.
She then returned on 4 January and again on 9 January. After receiving no response on this third attempt, she alerted Mr Battersby's landlady and gained entry.
Speaking to BBC Breakfast, Ms Battersby, 37 - who has the same father as Bronson but a different mother - said that had social services been told about her father's health issues after they were first unable to contact him, it "could've been a different outcome for my baby brother".
More information at bbc news.