Stoke mother Samina Kauser has been jailed after "allowing" on-off boyfriend Keith Brown to kill her two-year-old son.
Khaleel Hussain was just weeks from his third birthday when Kauser left him at home with Brown as she went shopping in October 2013.
When she returned, the boy had sustained a significant head injury at the hands of Brown, who in recorded 999 calls claimed the child had fallen down the stairs.
Hussain was taken to a local hospital before being transferred to the Children's Hospital in Birmingham, where he died the next day.
During Brown's trial at Leamington Crown Court jurors heard how a pathologist's examination also revealed Hussain had had his airway and breathing restricted for a period of time, causing bleeding into his lungs. This had probably occurred one to two weeks earlier.
The court also heard harrowing evidence detailing how a week before his death, Khaleel had been smothered with a duvet by Brown after crying at bedtime. Kauser challenged Brown and told him to leave her son alone but Jonas Hankin QC said that Kauser knew from Khaleel's long and subdued silence after Brown had left the room that he had been harmed.
Brown repeatedly lied during questioning, denying being in any form of relationship with Kauser, while Kauser said she did not know how her son became fatally injured. Both denied having any contact with Khaleel on the morning of the incident.
But on 17 July, jurors took just 10 hours and 12 minutes to return a unanimous guilty verdict and on 21 July Brown was sentenced to life and told he will serve a minimum of 15 years.
Kauser was given a three-year sentence after being found guilty of allowing the death of a child by failing to take steps she could reasonably have been expected to protect him.
Detective Inspector Jim Foy, from the Public Protection Unit in Coventry, said: "This was a difficult case as there were no witnesses and no CCTV showing what led to Khaleel's death. The police investigation was built on the string of lies told by Brown and Kauser.
"During sentencing, the judge highlighted two aggravating factors: Khaleel was left with Brown, who breached his position of trust and responsibility, and he did not ring for an ambulance for 20 minutes. These factors have led to him being handed a life sentence today."