Curtis Warren, 34, is waiting to hear if he will be freed after his appeal against the sentence for smuggling drugs worth pounds 120m into Britain.
Yesterday the Dutch Justice Ministry said he was being questioned after witnesses claimed he beat to death his Turkish cell mate, who was serving a life sentence for murder, in an exercise period.
The Dutch Justice Ministry spokeswoman said: "We are trying to find out the cause [of the fight] but guards saw the Turkish man head-butting Warren. They don't know the reason or what was behind the apparent vendetta. Curtis punched him back and within seconds they were hitting out and kicking each other and rolling over on the ground. Because of very real security fears the guards' priority was to get the other prisoners out of there as quickly as possible. They felt it would be too dangerous to separate the men fighting while other prisoners were in the immediate vicinity.
"When the guards returned they saw Curtis Warren standing over the other man, who was lying on the ground, obviously badly injured." He was rushed to hospital and put on a life-support machine, but he died yesterday morning of a brain haemorrhage. Officials were awaiting the results of a post- mortem examination on the dead inmate, who has not been named, to establish whether he died as a result of being hit by Warren or whether the haemorrhage was caused by the Turk head-butting Warren.
Warren rose from Toxteth, Liverpool, to accumulate a fortune estimated at pounds 40m. He was described as Britain's biggest drug-trafficker after being jailed for trying to flood the country with cocaine, heroin, ecstasy and cannabis. His name became familiar to television viewers in a documentary about Merseyside police which climaxed with the arrest and later conviction of the drug-squad chief Elmore "Elly" Davies for being in Warren's pay.
Warren was jailed at The Hague in 1997 for bringing in cocaine from South America, heroin from Turkey and cannabis from Morocco, using the Netherlands as his distribution base. He left Toxteth to live in a villa near Amsterdam in 1995 after a Liverpool gangland murder and his acquittal on a cocaine-smuggling charge.
His appeal is based on the activities of British security personnel working in Holland who allegedly passed on information about him illegally to police on Merseyside who were investigating Davies. Warren's lawyers claimed that had this conduct been known to the Dutch court, it would not have allowed the trial to proceed.