Jordan McSweeney, who stalked and murdered Zara Aleena, has won a Court of Appeal challenge to have his minimum tariff of 38 years reduced.
In a ruling on Friday, three judges found the sentencing judge had imposed too high an "uplift" to McSweeney's minimum term, and cut it to 33 years.
McSweeney had been released from prison on licence nine days before the murder.
Ms Aleena's family described the Court of Appeal's decision as a "shallow triumph" for McSweeney.
He had admitted murder and sexual assault but refused to attend his sentencing hearing last December, when the original tariff and a mandatory life sentence were imposed.
Last month, McSweeney, 30, left a Court of Appeal hearing after about 45 minutes.
'Repugnant man'
The sexual predator targeted at least five women before he attacked 35-year-old Ms Aleena as she walked home from a night out in Ilford, east London on 26 June 2022.
The attack on Cranbrook Road lasted nine minutes and resulted in 46 separate injuries to the law graduate.
In a statement Ms Aleena's family said: "Today's decision, a decision to reduce the minimum sentence for that repugnant man, aligns with an established legal sentencing framework, a framework we comprehend.
"Yet, the message it conveys to women is disheartening, suggesting that a 'life sentence' may not truly mean a lifetime behind bars. It is, in all honesty, a shallow triumph for him," they said.
"Despite his sentencing to a minimum of 33 years, his time in incarceration has been marred by abhorrent conduct, marked by a lack of remorse and a callous attitude toward others.
"The prospect of his release after 33 years remains slim, but, naturally, we hope he remains imprisoned for life."
McSweeney's barrister George Carter-Stephenson KC had argued that the sentencing judge, Mrs Justice Cheema-Grubb, had wrongly factored in the "aggravating features" in the case.
Mr Carter-Stephenson said it was accepted there was a sexual motive to the crime, but argued the murder itself was not premeditated.
He added: "The attack was an opportunistic act rather than anything that was planned in advance, though there was clearly a sexual encounter in mind.
"He planned to look for a sexual encounter, with or without consent."
However Oliver Glasgow KC, for the Crown Prosecution Service, said the suggestion McSweeney had not intended to kill Ms Aleena was "unsustainable".
'Hours of premeditation'
Mr Glasgow said: "The submission that the intention to murder Ms Aleena was formed 'on the spur of the moment' flies in the face of the applicant's behaviour preceding the violence.
"The sexual assault of Ms Aleena was the culmination of hours of planning and premeditation."
McSweeney stalked Ms Aleena along Cranbrook Road before grabbing her from behind and dragging her into a driveway.
The attack lasted nine minutes, during which the trainee solicitor was stamped on. She was found struggling to breathe and later died in hospital.
