It is possible that, because of the cleft palate, the baby aspirated some milk into her lungs. These babies require careful feeding often with a special teat on the bottle
// is thought to have been murdered // and ‘murdered’ in inverted commas seems to suggest that it is mot confirmed that she was murdered.
She obviously died in the care of someone, presumably the father. But it might have been an accident or could have been a medical problem, hence the report is careful not to say he did murder her.
I suspect more details will be revealed after a post mortem.