A man who was detained under the Mental Health Act was beaten in an ambulance by police, left handcuffed on the floor of a hospital ward and injected in the head by an officer just days before he died, his family told an inquest.

Kingsley Burrell, 29, died at the Queen Elizabeth Hospital (QE) in Birmingham on March 31 2011, four days after he was sectioned following a disturbance at a shop in the city.

Emergency services were called on March 27 after Mr Burrell, a father of three, dialled 999 to say that armed gang members had "put a machine gun" to his head while he was with his four-year-old son.

But CCTV footage shown to the jury suggested no one had threatened him, and instead he had become very agitated while at the shop, gesticulating wildly. He was taken to a mental health unit and died four days later after a cardiac arrest.

His family - many of whom wore red T-shirts with his photo and the slogan "Justice for Kingsley Burrell" to Birmingham Coroners Court - told the inquest he had claimed he was hit by a police officer in the back of the ambulance when he was first detained, was left with "lumps" on his face after being treated at mental health units in the city and was denied water while left handcuffed on the floor for up to six hours.

They also said he told them that police called to a hospital ward had covered his head and injected him "into his brain".

But police officers told the family he had gone "berserk" in the ambulance and attacked his own son, they said, banging his head on the floor and walls and had to be restrained.

Kadisha Brown-Burrell, Mr Burrell's sister, said that when she visited her brother with his partner, Chantelle Graham, at the QE's Oleaster mental health unit soon after he was first detained he appeared "very stiff" and could hardly move his head, body or shoulders.

She said: "Kingsley had three lumps, one on his forehead. I said to Chantelle, 'Take a picture of that'.

She added: "Kingsley was barefoot and had pyjama bottoms on. I could see that he was really upset, saying, 'How can they put me in here knowing I was calling for help because there were a couple of guys after me?'"

The following day he told them he had been handcuffed for a number of hours during an assessment at QE.

Ms Brown-Burrell said: "They had made him incontinent and he had wet himself. He was on the floor for five or six hours and all he wanted was water and for them to release the cuffs."

Mr Burrell told her a police officer had offered to loosen the cuffs for him, but "instead he tightened them", she told the court.

She later said he told her that he had been involved in a struggle in the back of the ambulance, and that three members of hospital staff had watched on at a mental health unit while police officers injected him into his brain.

She said: "Kingsley said, 'They have drugged me up in my head, they have injected me into my brain.'

"When I went to see Kingsley he said the police gave him injections into the top of his head, while three mental health staff looked through a window."

Ms Brown-Burrell described her brother, a student who lived in Winson Green, as "calm, collected and outgoing" and said there had never been any suggestion that he had mental health problems.

But the inquest heard he had been worried about a paternity issue and had been trying to get an ex-partner, Charmaine Clarke, to allow a DNA test to prove that he was the father of her son.

The jury was told Mr Burrell believed that on the day he was detained two men had followed him to a corner shop to threaten him over the paternity issue, and that he believed the only reason he was not shot was because he had his and Ms Graham's four-year-old son Kayden with him.

In a 999 call played to the inquest Mr Burrell repeatedly told the operator: "They put a machine gun to my head. It is called a Mach 10", adding that "a couple of black youths and one Asian" were waiting for him outside the shop, and that one had a machine gun in his back pocket.

He said: "I want police in the shop now, they are outside waiting to get me. I am scared for my life", adding: "I am so scared I nearly died. I cannot believe it. He pulled out the gun and put it to my head."

Mr Burrell also claimed that one of the men was the leader of the Burger Bar Crew, a notorious Birmingham gang. But the CCTV showed that while two men entered the shop in Winson Green, there was no suggestion of a threat towards Mr Burrell or any weapons, which police later confirmed.

Andy Gillespie, a firefighter who was one of the first on the scene, said Mr Burrell "very distressed", struggled to make eye contact was gesticulating and animated while he was on the phone to emergency services. In a previous statement Mr Gillespie said that when he approached Mr Burrell he told him he was a "fucking dead man", saying: "Two people are trying to kill me. I will be dead in 24 hours."

He said Mr Burrell told him: "I want everyone here for protection, I am a dead man. Somebody put a gun to my head, there is guys down the road, I am a dead man."

Footage showed him repeatedly pressing his hands together in prayer, and Mr Gillespie said he was saying, "Praise God, praise Allah".

He said: "It was almost that he felt relieved that he hadn't been shot."

Ms Graham told the inquest that when she went to pick up her son from a police station an officer told her Mr Burrell had "gone berserk" in the ambulance, had banged Kayden's head against the wall and that he had to be restrained to get the boy away from him.

But her son told her a black police officer had started hitting Mr Burrell. She said: "Kayden just kept saying, 'The black police officer hit my daddy' to anyone who would listen. That is what he told everyone, even at school."

Ms Brown-Burrell also said that in the days after Mr Burrell's death, Kayden had said, "The naughty black policeman did that to daddy."

The inquest also heard that Mr Burrell had been carrying a CS canister on the day he was detained, as well as claims that he was a gang member and drug dealer. Ms Graham said he was not a heavy drug user and smoked two rolls a day. The inquest continues tomorrow and is expected to last six weeks.