A police officer accused of the murder and manslaughter of former Aston Villa footballer Dalian Atkinson shot him with a Taser for 33 seconds - more than six times longer than recommended, a jury has heard.
PC Benjamin Monk, 42, is on trial at Birmingham Crown Court and has denied any wrongdoing leading to Mr Atkinson's death.
Opening the prosecution case against the West Mercia Police officer, QC Alexandra Healy told jurors the standard default setting of a Taser is a five-second phase, but it is possible to override that by continuing to depress the trigger.
"PC Monk continued to depress the trigger for more than six times the length of a standard five-second phase," she said.
"The Taser was deployed for 33 seconds."
Jurors also heard the 48-year-old former footballer, who also played for Ipswich Town and Sheffield Wednesday, was kicked twice in the head by Monk "with enough force to leave the imprint of the pattern of the laces from the top of his boot on two separate areas of Mr Atkinson's forehead".
His colleague, PC Mary Ellen Bettley-Smith, 31 - known as Ellie - is also on trial alongside Monk, charged with assault.
"She struck Dalian Atkinson repeatedly with an extended baton whilst he was lying on the ground, having been incapacitated on the ground by Taser," Ms Healy told the court.
Bettley-Smith has pleaded not guilty to a charge alleging she assaulted Mr Atkinson occasioning actual bodily harm before his death on 15 August 2016.
Ms Healy told jurors that pathologists and a specialist in intensive care instructed by the prosecution had concluded that while Mr Atkinson's underlying health conditions meant he was at a greatly increased risk of dying, were it not for the third Taser deployment and the kicks to his head, he would not have died that night.
Both officers were responding to a 999 call reporting a disturbance at Mr Atkinson's father's address in Meadow Close, Telford, at around 1.30am.
Mr Atkinson, who suffered from several health issues including high blood pressure and heart disease, had become "disturbed and erratic", the court heard.
He was shouting in the street which woke one of the neighbours who called the police.
Mr Atkinson answered the door and was "unarmed", continued Ms Healy, and Monk attempted to taser him twice, but the gadget was "ineffective".
The ex-footballer punched a glass panel in his father's front door "causing it to smash", before a further confrontation between him and the officers in the street where Monk fired a third Taser cartridge at him successfully, before kicking him in the head as he lay incapacitated on the ground.
Ms Healy said the two defendants claim they were entitled to use force because they feared for their safety.
"In kicking Dalian Atkinson in the head not once, but on two separate occasions, PC Monk was not, the prosecution say, acting in self-defence or in defence of another," the prosecutor continued.
She added: "In kicking Dalian Atkinson to the head PC Monk can only, the prosecution say, have only intended to cause really serious injury."
A pair of forensic scientists examined Monk's right boot and found bloodstains "on the laces and on the underlying tongue" which belonged to Mr Atkinson.
One of the scientists, Penelope Griffiths, said that in her expert opinion these findings could be explained if Monk had kicked Mr Atkinson "after he was already injured and bleeding".
Ms Healy went on to say that, when an officer known as Sergeant Sanders arrived at the scene, Mr Atkinson's pulse was checked and it "appeared to be very weak".
The court heard an ambulance was called but Mr Atkinson, who had lost consciousness and was unresponsive, went into cardiac arrest en route to hospital and was pronounced dead at 2.45am.
The trial continues.