An investigative report into the devastating Nov. 18 Berkeley fire released Monday determined the origin of the five-alarm fire but was unable to determine the exact cause of the blaze.

The report, conducted by Berkeley Fire Department, concluded that the Haste Street fire was accidental and that it “originated in or around the elevator resistors” in a basement room but was not able to determine whether the fire began due to “mechanical malfunction or improper installation of associated elevator equipment.”

The fire was the largest in Berkeley in more than 20 years. It began shortly before 9 p.m. and raged for roughly six hours, destroying the historic five-story Sequoia Apartment building and two restaurants located on the bottom level. Though their homes were destroyed, none of the building’s 68 tenants was injured.

The fire was first discovered by a tenant and a maintenance man who noticed smoke coming from the elevator room. The two attempted to put out the fire using fire extinguishers but were ultimately forced to retreat as the fire continued to grow, according to the report.

The report claims that although firefighters were able to extinguish the fire in the elevator room relatively quickly, the flames had already spread to other parts of the building.

“The building was built in 1916,” Berkeley Fire Department Deputy Fire Chief Gil Dong said. “The open construction used at that time did not include any fire stops. Once the fire reached behind the walls and ceiling and up the elevator shaft, there was nothing to stop it.”

Dong said that even by the time the first fire engine had arrived, firefighters noticed that the flames had already spread to both sides of the building.

According to the report, a private fire investigation firm called Fire Cause Analysis — hired by the building owner’s insurance company — removed the elevator equipment after BFD conducted its investigation for “further forensic examination” but promised to share its eventual findings with the department. Dong said the private firm had not responded with its findings yet and that no time frame had been set for the response.

Although the report does not mention it, according to the California Department of Industrial Relations, the building’s elevator permit expired on Aug. 12, 2011. The elevator had not been inspected since August 2010 due to a backlog in the inspection agency, according to the department.

Since the fire, tenants have complained that maintenance issues in the building were long ignored by the owners, including problems with the elevator and electrical wiring. Many of the tenants are planning to file individual lawsuits against the owner for negligence that led to the loss of their homes and personal belongings.

Former tenant Hooman Shahrokhi said he thinks that some of the liability for what happened falls on the owner.

“Based on my research, it’s based on building character,” Shahrokhi said in reference to the potential repercussions of the lawsuits. “There was some negligence on the owner’s behalf, and even after the fire, there was shady business going on.”

In 2006, Shahrokhi won a lawsuit against the building owners after losing his laptop and bedspread to a small fire that started after he plugged a power cord into an outlet in his apartment.

During the course of the demolition, some tenants complained that the demolition process was rushed and worried that inspectors may not have had enough time to thoroughly investigate the fire’s origin.

The report notes that the fire inspector had a “limited timeframe to attempt to make entry into the structure to conduct an origin and cause investigation before the building would be inaccessible or totally destroyed.” However, Dong said fire staff did have sufficient time to conduct their investigation, though they were working under the assumption that the building was going to be demolished very soon.

The building owners could not be reached for comment.