A man has been given a whole-life prison sentence for murdering his girlfriend a year after his release for killing a previous partner.
Paul O'Hara, 41, burst into Cherylee Shennan's home as she reported his domestic abuse to two police officers.
He attacked the trio with a hammer before chasing Ms Shennan, 40, into the street and stabbing her to death.
Preston Crown Court heard O'Hara admit to murder and the wounding and assault of the two officers.
'Dangerous to women'
O'Hara, of Honiton Close, Greater Manchester, was given a life term for murder in 1998 after killing a previous girlfriend in "very similar circumstances".
He was released on licence in 2013.
Lancashire Police said Det Sgt Damien McAllister and Det Con Karen Kenworthy went to Ms Shennan's home on the 17 March after the probation service referred domestic abuse at the hands of O'Hara to the force.
But, within minutes of their arrival, O'Hara forced his way into Ms Shennan's cottage on Hardman Lane, Rawtenstall, and set about the former beautician with a hammer, before turning on the police officers as they tried to intervene.
Ms Shennan fled her home but the court heard neighbours witnessed her kneeling in the street as O'Hara "methodically" rained down blows.
She was pronounced dead at the scene and a post-mortem examination found she died of multiple stab wounds.
In sentencing O'Hara, Recorder of Preston, Judge Anthony Russell QC, said he was "very dangerous to women".
He gave the killer 10 years for attacking Det Sgt McAllister and two years for the assault on Det Con Kenworthy, to run concurrently to his whole life term for murder.
Det Supt Eddie Thistlethwaite described Ms Shennan's death as "truly horrendous".
He said: "O'Hara is a predatory and violent individual who manipulated his victims including Cherylee, praying on their craving for love and attention.
"He has shown no or little remorse throughout this process and his actions fully justify the sentence which has been imposed."
Ms Shennan's family said in a statement they had "torn apart and tormented" by her death and their "lives will never be the same again".
The family praised Lancashire Police "particularly the officers who tried desperately to save Cherylee's life".