OKLAHOMA CITY (KFOR) – Officials say the investigation into a massive apartment building fire that burned for days is taking longer than expected.

In February, Oklahoma City firefighters were called a fire at The Canton at Classen Curve, a five-story apartment building near N.W. 63rd and Western.

Officials say the fire was extremely hard to put out, adding that a garage collapsed at one point. Crews believe the roofing material made it hard to contain the massive fire.

“Again, this is a very large complex that is being built. When we got here, there was basically smoke on the roof and a smaller amount of fire when we first arrived. But what we realized was the roofing material is a rubberized roofing material that basically it doesn’t go out well with water,” said Batt. Chief Benny Fulkerson, with the Oklahoma City Fire Department.

Multiple agencies were called to the scene to help fight the five-alarm fire throughout the night.

It took four days to put the fire completely out, and then the structure was demolished.

Now, fire officials say the investigation into what sparked the fire at the complex is taking longer than they anticipated.

Initially, the Oklahoma City Fire Department said they hoped they would be finished with their investigation by the end of this month.

However, authorities say that isn’t going to happen.

They say they are no longer offering a timeline for the completion of the investigation due to the complexity of the case.

The 326-room luxury apartment complex was scheduled to open sometime in the spring with apartments starting at 600 square feet, ranging from $1,100 to more than $4,000 a month.

The complex was valued at over $65 million and is a total loss.