A British dad who was allegedly knelt on by police and beaten up by bouncers in Spain died after being injected twice with super-strength painkiller fentanyl, his family said.
Tobias White-Sansom, 35, slipped into a coma and died in hospital on July 31 last year - five days after the incident on the Magaluf strip in Majorca.
His family petitioned for his body to be released by Spanish authorities and flown home, before finally laying him to rest in his home city of Nottingham last October.
They have since discovered that, shortly before going into cardiac arrest, Tobias was injected with fentanyl by medics, whom they claim were acting under the orders of police.
A medical report seen by the Mirror shows that two doses were given intravenously - once while he lay on the ground outside the nightclub and a second time inside an ambulance.
Fentanyl is a strong opioid painkiller which can be used to treat severe pain, such as during or after an operation, according to the NHS. It is up to 100 times more potent than morphine.
Tobias' brother Maximillian White said: "Realistically, I think that Toby died from the fentanyl which they injected him with.
"They pulled him outside the club while he was semi-conscious and handcuffed. They sat on him while he was shouting about not being able to breathe and they then decided to give him an injection.
"It was after that injection which sent him into cardiac arrest. Then when the ambulance came and he was okay, they gave him another injection and that took him into cardiac arrest again. Are the police allowed to do that?"
While the exact quantity of fentanyl administered to Tobias is unknown, it is much more potent than heroin and a very small amount can cause severe clinical effects or death.
Those who do take it are advised not to drink alcohol, and usually start on a low dose of another type of opioid, such as morphine.
Maximillian continued: "If the police were trying to say that Toby was being aggressive, then why would you inject him with fentanyl?
"And if he was passed out, then why would you inject him with fentanyl, not adrenaline or something?
"However you want to look at it, it doesn't seem right what they did. They can say that Toby died days later at the hospital, but Toby died outside that nightclub on those streets by himself, after he was injected the first time.
"Because after that - they managed to resuscitate him after 25 minutes - he was dead. All they did was bring his pulse back, and then they put that pulse in an ambulance, injected him again, and he went again.
"He never really had a chance, and it's terribly sad because I'm going through this stage where I can't remember what it was like to have him around.
"His children are getting older and I'm trying to do my best by them that I can, while also dealing with some heartache of my own."
More than 7,000 people in Spain died from opioid overdoses between 2010 and 2017, according to data from Cádiz University’s Pain Observatory which was reported by El Pais.
The number of overdoses increased over that period, from 700 a year at the beginning to more than a thousand in the last two recorded years.
Spain has also seen a rise in its prescriptions for rapid-release (oral or nasal) fentanyl, which doubled between 2010 and 2016.
This led to the Spanish health ministry updating its prescription guidelines, and finding that a "high percentage of treatments do not comply with the authorised conditions of use for these drugs".
It added: "The information analysed shows that the overall consumption of fentanyl in Spain has increased in recent years.
"Within the scope of the National Health System, there has been a progressive increase in the use of immediate-release fentanyl preparations, with consumption doubling in 2016 compared to 2010, a higher use than in other neighbouring countries."
Tobias' cousin, Ricardo White, questioned why the father-of-two was injected with fentanyl.
He told the Mirror: "Obviously with it being such a dangerous drug, when you inject it, a slightly wrong amount can cause cardiac arrest, and that's what happened - he went into cardiac arrest.
"They then resuscitated him, which took them 25 minutes, put him in the ambulance and they administered a second dose of fentanyl, and then he slipped into a coma.
"The police say that they ordered the ambulance to make an injection because he was uncontrollable. And all the videos that we have show that when police brought him out of the club, he was actually semi-unconscious.
"His head was rolling back, he'd been beaten by the bouncers, he was unable to fight anything."
Acting Senior Coroner Andrew Barkley, of Staffordshire South Coroner’s Service, previously decided that an inquest into Tobias' death will be necessary.
But Tobias' family has been unable to move forward with the inquest to date, and have been pushing the coroner's office for directions and a timetable.
Labour MP Nadia Whittome has also written a letter to Mike Freer, the Parliamentary Under Secretary of State for the Ministry of Justice, in an attempt to speed up the proceedings.
She told the Mirror: "It has been over nine months since Tobias’ death in harrowing circumstances, yet his family are still waiting for answers, let alone for those responsible to be held to account.
"I have written to the minister in charge of courts and legal services, urging that an inquest take place as swiftly as possible."
Tobias' family previously told how a night out turned to tragedy when they visited the Boomerang nightclub last year.
Police said at the time that private security informed them of an assault on a bouncer, and the suspect was given a tranquiliser before being taken to hospital, where he died.
But witnesses alleged that Tobias was "in no way resisting" and that he was seen with "blood pouring from his face" inside the club.
They claim bouncers hit and kicked Tobias, before "pinning him to the floor" while he "screamed non-stop".
Witnesses also alleged that once Tobias was brought outside, police "hit him with batons" as well as other "people in the crowd".
Eight police officers then knelt on Tobias, it was claimed, before he was taken to hospital by an ambulance.
At the time, the Spanish civil guard said it was called to reports of an assault of a bouncer.
It said in a previous statement: "Upon the arrival of the Guardia Civil police, this man was violent and police reduced him to be assisted by medical services. He was taken to the hospital for treatment.
"There, once while he was being assisted, he was arrested for a crime of injury."
Meanwhile, an FCDO spokesperson said: "We provided consular assistance to the family of a British man who died in Mallorca."
The Mirror has contacted the Spanish civil guard for further comment.