They discovered a body at the property which has now been identified as Asghar Badshah, 39, who was missing from Bradford.
Mr Badshah was last seen in the early hours of November 30 and reported missing on December 4.
West Yorkshire Police have launched a murder investigation following the grim discovery and three people have been arrested.
Detective Chief Inspector Heather Whoriskey, of the Homicide and Major Enquiry Team, said: “Enquiries are continuing into the death of Mr Badshah, who was reported missing on December 4.
“We believe he was last seen in the early hours of November 30 and I would appeal to anyone who has witnessed any suspicious activity in Commercial Street around that time or since to contact my team, so we can establish if this is linked to our investigation.”
Two men aged 27 and 30, and a 41-year-old woman, have been arrested on suspicion of conspiracy to murder.
Both men have been released under investigation and the woman is on bail pending further enquiries.
Mr Badshah's family say they are "devastated" after being informed of his death and they have paid tribute to the 39-year-old.
In a statement, the family said: "We as a family are deeply shocked and devastated by the loss of our dear brother Asghar Badshah.
"His beautiful smile and charisma, as well as his generosity will never be forgotten.
"We as a family please ask for privacy during our time of grief as our elderly mother is deeply upset at this time.
"We pray for justice for Asghar and appeal to the public for any assistance they can provide to the police in this investigation.”