The announcement on Monday comes just days after the Bureau of Alcohol, Tobacco, Firearms and Explosives became involved in the investigation into what caused the devastating blaze.
VIDEO: Video shows pets rushed to safety during SJ Home Depot fire
Video shows pets rushed to safety during SJ Home Depot fire
District Attorney Jeff Rosen along with the ATF, the San Jose Fire Department, Mayor Sam Liccardo, and the San Jose Police Department will be holding a news conference on Tuesday to release more details about the arrest and the charges against the suspect.
The ATF and San Jose Fire have asked that people who were at the Home Depot when the fire started, come forward and give their account.
Witnesses who spoke with ABC7 News claimed there was no immediate fire alarm and no sign of active sprinklers. The fire department said that is all under investigation.
"We were watching the ceiling come down in flames before any alarm came on," said Jeff Bahm, who was inside during the fire. "It wasn't until maybe three minutes after we left, this giant plume of smoke came rushing out to the front and then we all knew it is time to leave."
"In this case, if in fact true, not having any suppression within the sprinkler systems... It's like, what happened? Was it overwhelmed? Was it not enough? Or was it shut off? I think those are the things that the fire department- now with ATF help- are gonna come out and present at some point," Schapelhouman shared.
He added, "You can overwhelm sprinkler systems- and we've seen that before in large warehouse facilities- meaning that the fire gets so big, the ability of the sprinkler system is not there to be able to put it out. So that's a design issue, that's a combustible load issue, that's a code issue. And those are all real factors."
VIDEO: As feds aid in SJ Home Depot fire investigation, industry experts share insight into process
Fire industry experts share insight into SJ Home Depot fire
When that time comes, he said what is ultimately identified could lead to widespread improvements.
"It's not as if that's the only Home Depot in the country, right?" he added. "Nobody's looking to duplicate this."