Alleged killer taunted love rival over ‘fantastic sex’ with her partner

Sarah Williams is accused of killing Sadie Hartley by stunning her with a cattleprod then stabbing her repeatedly

Sarah Williams planned attack on rival with 'delusional hope' of winning her ex-partner back, Preston Crown Court heard (Getty)

A woman accused of murdering her love rival had previously sent the victim a letter boasting of having “unbelievably fantastic sex” with her partner, a court heard.

Sarah Williams, 35, wrote to Sadie Hartley, 60, after her former partner Ian Johnston, 57, had begun a new relationship with Ms Hartley.

Mr Johnston, a former fireman, had ended the relationship with Williams after she became “possessive and difficult”.

In the letter, Ms Williams wrote: “The sex is unbelievably fantastic, the best he's ever had by a really, really long way. We have never been able to get enough of each other.

“It satisfied a need in him he will never really be able to suppress or manage without.”

Preston Crown Court heard that after the letter failed to break up the couple, Ms Williams then attacked Ms Hartley on the doorstep of her home in Lancashire using a cattleprod to stun her, and then stabbed her 24 times, the Mirror reported.

The attack came 18 months after Mr Johnston ended the relationship with Ms Williams. But prosecutors said Ms Williams planned the attack with the “delusional hope” of winning Mr Johnston back.

Ms Hartley, a mother of two, was found dead in the doorway of her house, the day after the attack on 14 January this year.

Ms Williams allegedly planned the attack with her friend Katrina Walsh, 56, with whom she travelled to Germany to buy the cattleprod.

The pair also discussed leaving an Isis flag at the scene of the crime in an effort to throw off the police, the court heard.

Ms Walsh later claimed to the officers arresting her that she thought she was on the survival television programme Hunted.

John McDermott QC, prosecuting, said: “Sarah Williams was obsessed with Ian Johnston.

“They had had a relationship in the past. Sarah Williams wanted that relationship back and she set her mind to it.

“A more cold-blooded plan you cannot imagine. It is chilling, we say, to realise that two women could become such determined killers.”

The trial continues.