An early morning construction fire in Oakland on July 7 that became a four-alarm conflagration the heat of which was detected from space and caused glass from a nearby building to spontaneously fall off, continues to be a mystery for investigators from the ATF (Bureau of Alcohol, Tobacco, Firearms, and Explosives). As the SF Business Times is reporting, investigators announced Friday that they've reached no conclusion as to the cause of the blaze, or whether it was arson.

This is despite numerous interviews with witnesses, and a "meticulous search of the burned out remains of the massive apartment complex," according to CBS 5.

The fire at 2302 Valdez Street, a 196-unit development near the Whole Foods and Lake Merritt dubbed Alta Waverly, broke out around 4:30 in the morning, and almost immediately caused speculation about a serial arsonist who could be connected to this and three other recent fires at construction sites in Oakland and Emeryville. Two of those occurred at the same development at 3800 San Pablo Avenue, the most recent in May. The ATF quickly announced they were offering a $110,000 reward for information leading to the capture of such an arsonist, but that has apparently not led to any leads. The best evidence they have so far is surveillance footage of a hooded bicyclist who was suspiciously in the vicinity of the Emeryville fire in May.

The ATF says they will be continuing their investigation, and developer Wood Partners said, "We are hopeful the AFT and fire officials can make a determination of the cause of the fire in the future."

Wood Partners has vowed to rebuild what they had started on this site, perhaps with the City of Oakland's help, and a completion date in 2019. As constructed the Alta Waverly had been set for completion next year.

Previously: Is The Same Bicycling Arsonist Responsible For Four East Bay Construction Fires?