A 15-year-old boy has been arrested over a string of alleged offences that began with an alleged knifepoint robbery on a train and ended with him allegedly threatening a woman in her home with a metal pole, as well as two kitchen knives.

The boy, who cannot be named for legal reasons, appeared in Perth Children’s Court on Tuesday where he was released on bail, despite prosecutors arguing there was little to no explanation for the alleged offending.

The Warwick teenager, who fronted court with a black eye, told the court he was being chased by a 17-year-old who punched him, leading to him allegedly putting a knife to a 16-year-old’s neck and demanding he hand over his phone.

Police claim the boy was in the company of another teenager on a southbound train between Whitfords and Warwick at the time of the alleged offence around 2.15pm Monday.

“The charges are very serious,” prosecutors told the court.

“The allegation is that he repeatedly assaulted the complainant.”

The prosecutor said members of the public nearby were “fleeing” in terror.

The court then heard the boy jumped off the train after the alleged robbery and broke into the house of a stranger on Hawker Avenue in Warwick, where he allegedly “armed himself with a metal pole”. He then allegedly “pulled out two kitchen knives” and threatened the woman.

The court was told the boy had no prior history of offending, was a dedicated school student and was a talented basketball and football player.

“We want to know how this has happened to someone with no record,” prosecutors said.