In October 2015 Hamza was convicted of 11 charges of terrorism and kidnapping and sentenced to life imprisonment in the US. Since then he has been kept in solitary confinement without the possibility of parole.
Mr Simionov had only been living in Britain for a few weeks after arriving from Romania. It is understood that he was working at a VIP party organised by the self-styled aristocrat ‘Lord’ Eddie Davenport, a convicted fraudster.
Footage of the incident shows the former boxer grappling with a number of men outside the luxury venue. One of the attackers is smashed over the head with a vase before staggering away.
Colleagues told how Mr Simionov had been stationed inside the apartment when the fracas began and came outside to protect other staff, three of whom were also stabbed during the attack.
It has also been reported that he was not due to work on New Year’s Eve, but had agreed to cover for someone else.
Mr Simionov’s fiancee told friends she would take his body back to Romania, adding that her loss was “impossible to understand”.
She said on her Facebook page: “My lover and the one who was going to be my husband, Tudor Simionov, was stabbed deep in the heart at work.
“It's hard for me to find the right words in these moments.
“The news of unexpected death has pained us all. Thank you all for your support.”
“They were attacked by a group of males who were outside trying to enter. The female was also attacked as she assisted the security staff in closing the front door.
“This shocking incident happened just hours into a New Year, the area was particularly busy with people out celebrating and making their way home.”