Almena was the leaseholder and founder of the hive-like artists' collective at the warehouse, known as the "Ghost Ship", where revelers had gathered on the night of December 2 for party when the warehouse went up in flames, claiming the lives of 36 people.
Derick Ion Almena, who leased out the 10,000-square-foot warehouse and turned it into an unsanctioned residence for artists, was arrested Monday morning in Lake County, and his partner Max Harris, the venue's "creative director", was arrested Monday in Los Angeles County.
Throughout the investigation, the District Attorney's Office worked with multiple agencies, including the Oakland Fire Department, the Oakland Police Department, the Alameda County Sheriff's Office, and the Bureau of Alcohol, Tobacco, and Firearms (ATF).
O'Malley said the felony charges are against property manager Derick Ion Almena, 47, who converted the warehouse into an artist residence and underground concert venue called the Ghost Ship, and Max Harris, who worked as the Ghost Ship's "creative director" and organized the concert that occurred the night of the fire on December 2.
"Almena and Harris knowingly created a fire trap with inadequate means of escape", O'Malley said at a news conference.
Almena is being held with bail set at $1 million.
Kyndra Miller and Jeffrey Krasnoff, attorneys who represent Almena, did not immediately return phone messages Monday. Several people were using the building as a live/work space.
City records also show that building inspectors had opened an investigation into an "illegal interior building structure" at the warehouse three weeks before the fire.
The cause of the inferno is expected to remain undetermined, Assistant District Attorney Teresa Drenick told the LA Times, citing the lack of evidence in the wake of the fire.
An official briefed on the investigation initially told ABC News that the power went out inside the building when the fire started and the flames blocked the building's only exit, making it hard for people inside to escape.
Ng, Almena, Harris and others were named in a lawsuit filed last month by the victims' families. "And on December 2nd, 2016, particularly, they actually blocked one of the points of egress, leaving only one way to get out of the second floor of that building".
"We continue to mourn the loss of 36 young and vibrant men and women. who should be with us today", O'Malley said. "Their reckless actions were the proximate cause of the death of the 36 individuals trapped inside the warehouse when the fire started", the statement continued.
On the day of the fire, Harris acknowledged he allowed the party to take place and prepared the space for the music event, blocking off access to a second stairwell, leaving only one escape route, Harbison reported in the document.
In addition to claims against Oakland and Alameda County, the Maddens and Gregorys targeted building owner Chor Nar Siu Ng and landlords Micah Allison and Almena.