Authorities also said that investigators searching Paddock's hotel rooms at the Mandalay Bay Resort and Casino, along with his vehicle and homes, found more than 20 guns, hundreds of rounds of unused ammunition, suitcases partially filled with "pre-loaded high capacity magazines", body armor, a homemade gas mask and explosive materials.
The result was 58 people dead and hundreds injured in the worst mass shooting in US history.
The documents, which were released in response to a lawsuit filed by several media organizations, include more than a dozen search warrant affidavits.
Mr. Paddock's motive for the attack remains unknown.
"While investigators obtained a DNA buccal swab sample from Danley", one search warrant request stated, "she spontaneously stated that her fingerprints would likely be found on Paddock's ammunition because she occasionally participated in loading magazines". "Neither contained significant information that allowed investigators to determine the full scope of Stephen Paddock's planning and preparation for the attack", the documents said.
Not much is known about Danley's and Paddock's relationship, though workers at a Starbucks in a Mesquite casino recalled that he had a habit of berating her in public.
"Investigators have been unable to figure out why Stephen Paddock would be exchanging messages related to weapons that were utilized in the attack between two of his email accounts".
At 2:46 a.m., her account was deleted, said the documents.
As of October, there was no evidence that Danley assisted Paddock in commission of the massacre, and she remained "the subject of intensive review", the documents say.
Police and the Federal Bureau of Investigation have said they found no evidence that Paddock had help carrying out the attack.
The records also show Paddock purchased most of his guns and ammo online in the 12 months leading up to the attack, and that he used anonymous communication tools and destroyed some of his digital footprints.
Clark County Sheriff Joe Lombardo later said that October 2 search found 19 guns and several pounds of potentially explosive materials. Their warrant gave agents authority to search for "trace evidence" including blood and hair fibers. Lombardo said several pounds of ammonium nitrate, a material used to make explosives, was found in the vehicle.
Other searches were conducted at a house the gunman owned in Reno, where agents found a red SUV and a neighbor reported that Paddock kept a safe the size of a refrigerator in the garage.
U.S. District Judge Jennifer Dorsey said she saw no reason to keep the warrants unsealed - especially since lawyers with the federal government did not oppose the unsealing, with some minor redactions.
Information for this article was contributed by Regina Garcia Cano and Michael Balsamo of The Associated Press.