— While investigators have maintained that they don't know what started a fire that damaged 10 buildings downtown last spring, a search warrant made public on Wednesday shines a bit of light on their investigation.

The five-alarm fire, believed to be the biggest in Raleigh in at least a century, roared through the night of March 16, 2017, leaving dozens of condo and apartment residents homeless, businesses and churches damaged and the under-construction Metropolitan Apartments, at 314 W. Jones St., a heap of ash.

No one has ever been blamed for the blaze, and investigators have come up empty in the search for a cause.

The search warrant details the Raleigh Police Department's search of Google accounts linked to any device in use in the area around the fire on the night that it happened.

"The information sought from Google regarding the subject accounts ... will assist in identifying which cellular devices were near the location where the crime being investigated occurred during the time frame it is currently believed to have occurred," the warrant states.

In seeking the warrant, police asked Google to provide "anonymized information" for any account that company could identify as being in the zone between 7:30 p.m. and 10 p.m. on the night of the fire. According to the warrant, the last contractor authorized to be at the Metropolitan left the property at 7:30 p.m. By 10 p.m., the building was engulfed in flames.

Google accounts and Android devices use location tracking in mapping apps and to deliver other location-based information to users. The movements of account holders who leave location services turned on are saved in Google's servers.

Police said in the warrant request that they would use the anonymized information to narrow down specific time and location coordinates that correspond to"known time and location information that is specific to this crime." They then asked Google for additional time and location data for any accounts identified and ultimately were requesting identifying information – user names, dates of birth, email addresses, telephone numbers and types of devices – for accounts that fit the profile.

Police also asked that the search, which was conducted on May 5, 2017, not be disclosed to Google users for at least 90 days. In making that request, Detective Brad Watson wrote, "The existence and scope of this ongoing criminal investigation is not publicly known."