MILWAUKEE (CBS 58) -- New documents shed light on what may have caused the two fires at a Walker's Point U-Haul facility earlier this year.

The first fire started January 21 when dozens of storage units were damaged in a massive blaze.

Then, just two-and-a-half months later, the building caught fire again.

The new reports from the Milwaukee Fire Department detail how first responders battled the massive fires, and what they believe may have sparked them.

The report says the January fire was likely due to an electrical malfunction. The cause of the April fire is more complicated.

It was just after 6:30 in the evening, January 21 when the 911 calls came in.

Milwaukee firefighters battle a fire at the Walker's Point U-Haul facility, January 21, 2026

The northeast corner of the U-Haul storage facility was on fire and spreading quickly.

According to the investigation report, two engine crews went into the building under "heavy smoke." But quickly, their low-air alarms started to ring and they were ordered out of the building.

Two U-Haul employees later told investigators they "heard what sounded like fireworks going off."

Milwaukee firefighters battle a fire at the Walker's Point U-Haul facility, January 21, 2026

When they went to look, they found there was a fire upstairs.

The fire investigator found a damaged transformer and said the cause of the fire was possibly electrical in nature.

That damage played a role in the April 6 fire, just 10 weeks later.

According to that report, We Energies refused to restore electric service after the first fire. So the owners hired a Germantown company to connect three generators to supply power to the building.

Milwaukee firefighters battle a fire at the Walker's Point U-Haul facility, April 6, 2026

But the fire detection and alarm system was out of service. So was the fire sprinkler system.

When engine crews arrived that night, they saw thick black smoke and felt high heat in the hallways. There was zero visibility and their low-air alarms forced them out of the building.

Investigators found the generators parked outside with five cables running under a locked door and into the building.

As to the source of the fire, the report says MFD is "unable to rule out responsibility of human fault, contributed by an intentional action with negligence or reckless conduct."

No one was injured in either fire.

It’s important to note that both reports say the cause of the fires are still under investigation.