Man guilty of murder and sexual assault of baby in WA's north

A 27-year-old man has been found guilty of sexually assaulting and murdering a 10-month-old baby in Western Australia's north.

The Supreme Court in Perth was told Mervyn Bell took the child from Broome and was alone with him for 15 hours before rushing his lifeless body into a roadhouse near Karratha, about 1,000 kilometres away.

The child had injuries from his head to his feet, including broken bones, burns and severe abrasions, the court was told.

Justice John McKechnie said it was "one of the more evil crimes that I have encountered" and told Bell he would be jailed for life when he is sentenced in December.

more: Man guilty of murder and sexual assault of baby in WA's north

A 27-year-old man has been found guilty of sexually assaulting and murdering a 10-month-old baby in Western Australia's north.

The Supreme Court in Perth was told Mervyn Bell took the child from Broome and was alone with him for 15 hours before rushing his lifeless body into a roadhouse near Karratha, about 1,000 kilometres away.

The child had injuries from his head to his feet, including broken bones, burns and severe abrasions, the court was told.

Justice John McKechnie said it was "one of the more evil crimes that I have encountered" and told Bell he would be jailed for life when he is sentenced in December.