The cause of the tower block fire which killed six people in south London has now been established but police said they were not yet able to give details.
A three-week-old baby was among the victims of the blaze at Lakanal House in Camberwell in July 2009.
Relatives of the victims and local MP Harriet Harman said they had been kept waiting "too long" for information.
But the "protracted and complex" investigation was still continuing, the Metropolitan (Met) Police has said.
About 30 people were rescued from the 12-storey council-run building on the Sceaux Gardens Estate, with nearly 100 families left homeless.
Initial tests by the emergency services found an electrical fault in a TV may have been to blame, and London Fire Brigade completed its investigation in April.
The Met said it knew the cause and how the smoke spread, and its investigation was "at an advanced stage".
But it would be "inappropriate" to reveal more before it was completed, the force added.
"Our thoughts are with the families of the victims at this difficult time," said Det Insp Rick Murphy.
"We know that they are still patiently waiting for all the answers as a result of our enquiries."
Initial tests found a faulty TV set was the source of the blaze.
But Louise Christian, a solicitor for the families, said until her clients knew what happened, "things are going to get worse and worse for them".
Ms Harman, Labour's MP for Camberwell and Peckham, said two years was "too long to wait for answers" and called for a "super-inquest" at the High Court.
"Every day the inquest is delayed is another day that bereaved relatives don't have answers," she said.