A TEENAGER was called “evil” by the mum of the five-day old baby he is accused of killing.

Katie Strawhorn made the comment in a video clip recorded by her boyfriend Jack Butterworth.

The couple had started dating in January 2016 before Katie fell pregnant.

But, jurors heard the pair struggled following the news and started to regularly argue.

Prosecutors claim Butterworth,18, later assaulted Katie last November.

It is stated Katie, 20, suffered “placental abruption” resulting in baby son Lucas being born by emergency caesarean section.

The child was said to have so severely injured that he died five days later in hospital.

The evidence emerged as Butterworth went on trial charged with the culpable homicide of his baby son.

The teenager denies the accusations at the High Court in Glasgow.

Katie recalled how they started seeing each other on New Years Day 2016.

They soon moved in together – staying at a number of properties in Kilmarnock, East Ayrshire – before Katie learned she was pregnant.

She said the relationship was initially “good” – but added they were then “unsettled emotionally and financially”.

The assault on the baby's mum is said to have occurred at a number of addresses in Kilmarnock when she was 36 weeks pregnant.

The indictment includes claims Butterworth did “kick her on the stomach” as well as chase her and cause her to “flee and fall”

It is also alleged he did “repeatedly inflict blunt force trauma on her head and body”.

The teenager faces a separate charge of assaulting Katie between January and November 2016.

The trial, before Judge Lord Ericht, continues.