An ex-boyfriend murdered a couple arriving for work at a high street store in Cardiff, after he searched online for "16 steps to kill someone and not get caught, " a court heard today.

Window dresser Zoe Morgan, 21, and warehouse worker Lee Simmons, 33, were stabbed to death by her former boyfriend at a Matalan store.

Hotel worker Andrew Saunders, 21, plotted their killing after accusing Zoe of cheating on him with her work colleague at the store.

A court today heard how Saunders researched the killing but was arrested within an hour of the killing on the main Queen Street shopping centre in Cardiff.

Lee Simmons and Zoe Morgan had been going out with each other for less than four months after striking up a romance while working together.

Miss Morgan broke up with "very controlling" Saunders after he accused her of cheating.

He sent her a message saying: "You're definitely chatting to someone else. I will kill whoever it is."

Cardiff Crown Court heard he viewed a video called '10 people who got revenge on cheaters'.

Saunders then search online for '16 steps to kill someone and not get caught', 'How long do murders get in prison?', 'How to get a gun illegally UK' and 'Three easy ways to make a bottle bomb'.

Before Saunders set off on the murder, he left letters saying, 'I think ISIS are the good guys most of the time and that's pretty messed up. No one will forget me.'

Lee Simmons and Zoe Morgan were attacked at 5.50am on September 28th as they arrived at the Matalan store.

Saunders was arrested in a dawn raid at the home he shares with his single mum Karen Saunders, 55, and sister Anna, 19.

Saunders, of Castleton, near Cardiff, admits murder.

He will be sentenced tomorrow.