After the bodies were found, Simpson-Kent wrote: “Sorry for the attention I have brought to your life"
But we can reveal he confessed to the triple killing before his arrest – in a text to his mum Selina Hoggett.
He had fled to his native Ghana after bludgeoning terminally-ill former EastEnders star Sian, 43, before taking a knife to young sons Zachary, eight, and Amon, four.
"Why? For months we discussed her options because of her illness and she told me if it got to a certain point she would like to die.
“And it got to that point. Why the children?
"Because the agreement without their parents there was no one qualified to raise them in the way they were accustomed to.
“Society was not an option neither was her family. So the final promise was we all go.”
His mum replied: “Arthur please don’t kill yourself. We love you.”
But instead of committing suicide, Simpson-Kent spent his last days of freedom in beachside bars before his arrest and extradition to the UK.
Worried relatives reported Sian and the children missing in December.
Read more: Tragic EastEnders actress Sian Blake buried next to murdered children - 108 days after they were found dead
He fled the UK and the victims were found three weeks later buried in the garden of the family home in Erith, South East London.
Actress Sian played Frankie Pierre in EastEnders in 1996-97 before motor neurone disease forced her to give up acting.
Simpson-Kent was jobless and dealt cannabis. Relatives said they led an alternative lifestyle.
Simpson-Kent appeared at the Old Bailey yesterday via video link from jail and admitted the three murders. He will be sentenced in October.
Outside court, Sian’s sister Ava said the family were “pleased and relieved”.
