TWO-year-old Liam Fee died as a result of "blunt force" trauma to his torso, a court has been told.

Dr Paul French carried out a post-mortem examination on the toddler two days after his death in Fife in March 2014.

The specialist paediatric pathologist was giving evidence on day three of the trial of Liam's mother Rachel Trelfa or Fee, 31, and her civil partner Nyomi Fee, 28, who deny murdering the toddler.

Dr French, 38, also told jurors that in a post-mortem exam at Glasgow's Southern General hospital, he recorded the toddler as having a low body weight for his age.

At the High Court in Livingston, he read from his report, stating that in his opinion the cause of death was "blunt force injury of the torso".

The murder charge alleges that the couple assaulted Liam at a house in Fife on various occasions between March 15 and March 22, 2014.

The women also plead not guilty to a catalogue of allegations of wilfully ill-treating and neglecting two other young boys, who cannot be named for legal reasons, over a period of more than two years.

The pair are accused of falsely telling others, including police, that one of the other young boys was responsible for Liam's death.

They deny the charges against them.

Dr French told the court he noted the toddler's weight as being lower at death than it had been recorded in notes eight months previously.

He said this was classed as evidence of "failure to thrive".

Advocate Depute Alex Prentice QC, prosecuting, asked the witness to explain what that term meant.

"He's not growing as we would expect him to," Dr French said.

The pathologist added that the causes for this could be "natural chronic disease, poor diet, behaviour problems or potentially neglect".

Reading from his report, Dr French told the court: "No natural chronic disease to account for the failure to thrive has been identified at post-mortem."