A woman who had known Dalian Atkinson since he was a baby has told a court she feared he was dead as a police officer "stamped" repeatedly on the former footballer’s head.
Jean Jeffrey-Shaw said she had to look away as the ex-Aston Villa striker was on the ground in August 2016 because it was "too much" for her.
Police were called after Mr Atkinson was heard shouting in the street in Meadow Close, Telford, waking one of the neighbours.
The prosecution alleges that PC Benjamin Monk murdered Mr Atkinson by kicking him in the head at least twice, while PC Mary Ellen Bettley-Smith allegedly struck blows with a baton out of anger.
Monk, 42, denies murder and manslaughter, while Bettley-Smith, 31, denies assault.
Mrs Jeffrey-Shaw was among several eyewitnesses from Meadow Close giving evidence at Birmingham Crown Court.
She lived next door to Mr Atkinson’s father, Ernest, for more than 50 years.
Mrs Jeffrey-Shaw said that after seeing two police officers walking "with purpose" nearby, and hearing a crashing noise, she saw a man in the street – who she wrongly thought was Mr Atkinson’s nephew – fall to the ground behind a car.
"One of the officers was saying ‘keep your head down’ and was stamping on his head," she said.
"The man lifted his knee up and stamped. One time he was knocking him so hard I had to look away. I couldn’t stand it. He went boom, boom, boom."
Claiming the man on the ground had been stamped on "several times more than once", Mrs Jeffrey-Shaw added: "I said to my husband: ‘He’s not moving, why is he telling him to keep his head down?’
"I was thinking he is dead, because he wasn’t moving," she added.
Mrs Jeffrey-Shaw said the female officer appeared to be frightened.
"After he was stamping on the head, the lady was panicking but the other officer was calm," she told the court.
Asked by prosecutor QC Alexandra Healy if she had seen any movement from the man while he was on the ground, Mrs Jeffrey-Shaw replied: "No, that’s why I said he was dead."
Under cross-examination from Patrick Gibbs QC, for Monk, the neighbour maintained she had not mistaken two kicks to the head for stamping.
Mr Gibbs said: "A suggestion I have is that the officer has not stamped down with the sole of his boot, but he has kicked Dalian in the forehead with the front of the boot, with the laces?"
Mrs Jeffrey-Shaw said: "He was stamping. He was putting his foot down. I had to look away, it was too much for me."
Asked by Richard Smith QC, representing Bettley-Smith, if the officer had looked frightened at the scene, Mrs Jeffery-Shaw answered: "Yes, she was frightened. She didn’t know what to do with herself."
Earlier, jurors heard the former footballer’s father said his son was not in his right mind when he was tasered.
Ernest Atkinson, who has since passed away, told investigators his son, who also played for Ipswich Town and Sheffield Wednesday, had grabbed him around the throat after "pounding" on the door of his home.
Mr Atkinson, then 85, gave his account to police on 23 August 2016, jurors heard.
Junior prosecution counsel Paul Jarvis summarised his statement and read it to the jury.
Mr Atkinson told investigators he had opened a window and asked his son what was wrong, and he had asked to come inside to talk.
The 48-year-old seemed upset, his father said, and he opened the door for him because he was banging on it.
Addressing the jury, Mr Jarvis added: "From inside the house Ernest could see and hear Dalian standing with his hands out and say ‘You are going to Taser me. I’m the messiah, you cannot hurt me’."
Mr Atkinson, who assumed the police would be able to calm his son down, then heard a bang as the glass in his front door was smashed.
The trial continues.