Police in Los Angeles are trying to piece together what drove a frail elderly man on a stabbing rampage before begging police to kill him and taking his own life.
Graphic police video shows Loc Duong, 67, repeatedly tasered as he lurches with a knife towards officers down an apartment corridor telling them 'I want you to kill me'.
His body is illuminated by laser sights but, when no bullet is fired, he leans against a wall and plunges the ten-inch blade repeatedly into his stomach before slumping to the floor.
'In the next several months the LAPD will continue to investigate and analyze this incident,' said Capt Kelly Muniz.
'We will continue interviewing any new witnesses that may come forward and complete forensic tests.'
Loc Duong, 67, begged police to kill him after they cornered him outside his LA apartment
Loc Duong, 67, used a ten-inch kitchen knife to critically injure one passer-by and kill another before turning the weapon on himself when police refused his demand to shoot him dead
A security camera caught the moment Duong claimed his first victim outside a store on the corner of 6th and Spring streets at 3.45pm on October 26.
Duong, dressed in a baseball cap and carrying a backpack, walks casually past the man before seemingly turning on impulse and swinging his large kitchen knife repeatedly at the man's head.
The force of the blows sends Duong himself sprawling backwards into the road before he picks himself up, waves his knife threateningly at horrified onlookers and strides off as they try to flag down a police patrol.
Officers who arrive were told the knifeman had gone to an apartment building in the 200 block of West 6th Street where more security footage caught the moment Duong casually stabbed another passer-by in the corridor before heading for his fourth story home.
Police stumble across the second victim dying on the floor as they head up to his apartment door and one yells: 'This is the LAPD; anyone in room 417 come out with your hands up!'
Seconds later Duong peeps out, still carrying the now bloodied kitchen knife in his right hand.
Security cameras caught Duong swinging wildly at a passer-by on LA's 6th Street before casually killing another in his nearby apartment block
Officers who chased Duong into the apartment block on West 6th Street found one of his victims dying in the corridor
Several taser strikes and rubber bullets hit Duong as he begins advancing towards the officers, still carrying his blade
Officers plead with the man to drop his knife as he raises it in front of his abdomen
The retort from a non-lethal round is heard as Duong tumbles back into his room, before he emerges again and another shot rings out.
'Hey put the knife down!' an officer yells as the group edges backwards down the corridor.
Several more rounds strike Duong as he begins advancing towards the officers, still carrying his blade.
Tasers are fired before Duong shouts: 'I want you to kill me.' 'No! Drop the knife!' an officer yells back, 'back-up, back-up!' he tells his colleagues.
'I want you to kill me,' Duong repeats. 'Drop the knife sir,' comes the response. 'Drop the knife or we will shoot you!' another adds.
More taser shots are heard as Duong begins stabbing himself. 'Drop the knife, don't do it sir!' one officer says before Duong slides to the floor.
Another taser is fired in a futile last attempt to strop Duong stabbing himself
The dying old man slumps to the floor and officers move in to arrest him and seize his knife
'Alright sir hold on, suspect's going to be down,' one shouts before the officers edge towards the now prostrate figure, kick the knife away from his outstretched hand and cuff his arms behind his back.
Duong and his second stabbing victim were taken to hospital where they were declared dead.
His first victim remains in a critical condition.
The LAPD's critical incident review division is preparing a report on the stabbings and the police response for the city's chief of police.