However, it wasn't until this weekend that it was turned over to criminal prosecutors at the Alameda County District Attorney's Office.
RELATED: Report alleges Ghost Ship fire started next door
Late last month, the lead prosecutor at the district attorney's office learned the draft report was sent to the the city attorney's office on the sixth floor of Oakland City Hall.
He immediately demanded that report and all of the materials associated with it.
Then, the report was finally emailed to the the district attorney's office this weekend.
However, officials at Oakland City Hall didn't disclose any information as to why the report was delayed by nearly three weeks.
Earlier Monday, a spokesperson for the district attorney's office sent ABC7 News a statement confirming they did get that report. The spokesperson wrote: "As you know, we are conducting the criminal investigation. And the report is part of that investigation. As such, it will not be made public."
Thirty six people died in the Ghost Ship fire, and it became one of the worst tragedies in Oakland's history.
Mayor Libby Schaaf and District Attorney Nancy O'Malley have both promised a thorough investigation of the events leading up to the fire.
But legal experts have pointed out, this delay in getting the report to the district attorney's office could pose problems if criminal charges are ever filed. "Why was that report given over to the city attorney? And secondly, why did the city attorney hold on to that report for at least three weeks? What was going on? What wasn't in the report? If it was going to the city attorney, be turned over simultaneously to both the D.A. and the city attorney, Retired Superior Court Judge Ladoris Cordell said.
Cordell says if anyone is criminally charged, their defense attorney's can easily raise this question in court.
ABC7 News went to talk with officials at Oakland City Hall, the city attorney's office, mayor's office, and city administrators office, but no one wanted to answer the basic question as to why was this report was held from the district attorney's office for so long.
Click here for all ABC7 News stories, videos, and photos from the Ghost Ship warehouse fire.