Dale Cregan put a hand grenade in the mouth of a man he held captive while on the run from police, a court heard.
Jermaine Ward, 24, claims one-eyed Cregan and another man Anthony Wilkinson, 33, also threatened to shoot him and his family while keeping him as a virtual "slave" for two weeks while they hid from police, Preston Crown Court was told on Tuesday.
Cregan, 29, was on the run after allegedly murdering father and son, Mark and David Short, during a deadly feud between families in east Manchester.
After a nationwide manhunt he lured Pc Fiona Bone, 32, and Pc Nicola Hughes, 23, to a bogus burglary report at a house in Hattersley, Greater Manchester, last 18 September.
When they arrived he opened fire without warning on the unarmed officers with a Glock semi-automatic gun before throwing a grenade at the dying policewomen before handing himself in.
Cregan had been a wanted man after Mark Short, 23, was gunned down in the Cotton Tree Pub, Droylsden, Manchester, in May last year.
It is claimed Jermaine Ward played an "integral part" in the later attack on David Short, 46, at his home in Clayton, Manchester, 10 weeks after his son was murdered.
The jury were read parts of Ward's statement to police and shown video recordings of him being questioned in detail by officers.
Ward claimed on the day of David Short's murder he had agreed to drive a Vauxhall Combo van for Cregan and he drove him and Wilkinson to Mr Short's home address.
It is alleged Cregan and Wilkinson chased David Short through his house shooting him repeatedly before tossing a hand grenade on his dying body and blowing him apart.
Ward claimed the pair told him to wait in the van with the engine running before they returned to the vehicle.
Ward told officers in interview: "I heard a bang, Dale has got blood on him. I knew something had happened, he's like, 'Drive! Drive!'
"I was shaking. He rammed a gun at the side of my head. He told me which way to drive."
Ward said an Asian male, who the prosecution say is co-defendant Mohammed Ali, then took them from Greater Manchester to West Yorkshire to hide and kept them supplied with food while in the apartment.
He told police he had his phone taken away and was kept as a "slave" in an apartment for nearly two weeks with Cregan and Wilkinson.
Miss Louise Brandon, prosecuting, told the jury: "They put a gun to his head and told him he was staying with them. If he tried to escape they would go to the hospital and kill his brother.
"Every time he asked them if he could go, they said they would kill him or put a gun to his head or put a grenade in his mouth.
"Once they put a grenade in his mouth."
The defendant said Cregan and Wilkinson spent time holed-up in the flat living "just normal, watching telly and having a laugh."
He told officers: "It came on about the reward and they were laughing. They said that was rare.
"Their face was on the news, that they killed someone."
Ward said Cregan and Wilkinson had a "heavy duty" bag with them with two black and one silver gun inside and around 20 hand grenades.
He said he thought Cregan was in charge more than Wilkinson.
"He was the one who kept threatening me and my family," he added.
"They said they would get their friends to go to my Mum's house."
After 10 to 12 days they took him out of the flat - and Ward said he thought they were going to kill him.
But he was kicked out of the van and made his way to a police station in Huddersfield to give himself up.
Ward maintains he only acted as a "get away" driver on the murder of David Short under duress.
He denies murder, one count of attempted murder and causing an explosion.
Cregan and Wilkinson along with Francis Dixon, 37, from Stalybridge, all deny the murder of David Short, the attempted murder of Sharon Hark on the same day, and a single charge of causing an explosion.
Wilkinson is additionally charged with possession of a firearm with intent to endanger life and Mohammed Ali, 32, from Chadderton, Greater Manchester, is accused of assisting an offender.
Cregan, Leon Atkinson, 35, from Ashton-under-Lyne, Luke Livesey, 27, from Hattersley, Damian Gorman, 38, from Glossop, Ryan Hadfield, 28, from Droylsden, and Matthew James, 33, from Clayton, are all accused of the murder of Mark Short at the Cotton Tree Pub, Droylsden on May 26 last year, and the attempted murders of three others also in the pub at the time - John Collins, Ryan Pridding and Michael Belcher.
They deny all charges.
Cregan has admitted the murders of Pc Bone and Hughes and faces life in jail.
A police raid on Wilkinson's mother's home, on Falconwood Way in Beswick, Manchester, recovered a 9mm Browning self-loading pistol in an Adidas bag, the court heard.
It was loaded with the safety catch off and four more bullets were loose in the bag.
The gun was swabbed and a DNA profile matching Wilkinson was found.
The jury heard of a letter written by Wilkinson while on the run sent to Lucy Latham, his former partner and mother of one of his sons and also addressed to other family.
It read: "Lucy sorry about everything I really am. Don't be scared no one will ever hurt you or my boys.
"Police are listening to every call. All I can say is I'm sorry and I love you and my kids. Burn this letter and don't speak in houses.
"Look after my boys for me. Think they (the police) will shoot us when they get us.
"Money will get dropped off for you.
"Sorry I can't speak to you, still love you both and things might come off for us both yet.
"Don't tell no one I have been in touch.
"Don't let my boy go down Clayton please."
The trial was adjourned until Wednesday morning.