Father-of-three Mr Xhindi, aged 43 and from Albania, died in the fire at a unit on the Premier Trading Estate, off Leys Road in Brierley Hill, at around 7.30pm last Thursday.
Two men were pulled from the blaze but Mr Xhindi died the following day in hospital. The other man, aged in his 20s, was taken to hospital but later discharged.
West Midlands Police believe both the men had been trafficked into the UK from abroad and were effectively being held against their will.
Officers say the unit, used to grow cannabis on an industrial scale, was locked meaning the two men had no way to escape.
Mr Xhindi's family have paid tribute to him today, saying: "Margaritis was a loving son, brother and wonderful father of three children.
“He had worked very hard most of his life to provide for his family.
“Margaritis has touched the hearts of everybody who knew him and we are devastated with the sad news.”
West Midlands Police are working closely with West Midlands Fire Service and their specialist investigation team to establish the cause of the fire. A full forensic examination of the scene is also taking place.
Detective Inspector Jim Mahon, from the force's homicide team, said: "Mr Xhindi’s death is simply tragic. We are working with colleagues from the fire service to establish the cause of the fire.
“We are also in the process of carrying out a detailed forensic examination of the scene to try and identify who was involved in the cannabis grow and as part of this, we are carrying out an extensive CCTV trawl of the area.
“A drone was flying over the unit when the fire first broke out and we have now spoken to the owner who is assisting us with our investigation."
Superintendent Jason Anderson, of Dudley Neighbourhood Policing Unit, added: “My thoughts remain with Mr Xhindi’s family at this desperately sad time.
“Local officers continue to support detectives leading this enquiry anyway we can.
“Drugs cause harm in our communities and we continue to work tirelessly to prevent organised criminality and the exploitation of vulnerable people in this way."
Anyone with video footage, or any information, is urged to call West Midlands Police on 101, quoting log number 3969 of June 4.
Alternatively, call Crimestoppers anonymously on 08000 555111.