In the report, Ms. Danley explained that she met Mr. Paddock while she was working as a high-limits casino host. At first, their relationship was romantic, but she said she noticed a decline in his affection that she believed to be linked to his health.

He had bad headaches, she said, was sensitive to chemical smells and would not shake hands with people. He often wore cotton gloves. He was not religious, she said, and would often say things like, “Your God doesn’t love me.”

In the months before the shooting, Mr. Paddock’s interest in guns intensified and packages began arriving almost daily. Ms. Danley occasionally accompanied him to the gun store or shooting range. But the report concludes that “Danley believed Paddock’s new found interest in guns was merely a hobby.”

Mr. Paddock paid for Ms. Danley to see her family in the Philippines before the attack, wiring her a total of $150,000 during the trip, which was meant to pay for a house there. Ms. Danley told investigators she was worried Mr. Paddock was trying to set her up there before breaking up with her. They rarely spoke by phone during the trip, and Mr. Paddock became evasive every time Ms. Danley asked where he was.

On Sept. 27, Mr. Paddock asked her over email if she wanted to stay longer. “She replied she was ready to come home,” according to the report. Several days later, she was on her way to dinner with her sister in Manila when someone called to say they should return home.

When they walked into the house, Ms. Danley saw her driver’s license photo on television and learned she was a “person of interest.” On Friday, Sheriff Lombardo said that Ms. Danley is not under investigation.

The report also summarizes interviews with several employees of the resort, including valets, bellmen, room service attendants and security officers. Each of the employees said there had been nothing remarkable about Mr. Paddock in the days leading up to the shooting.