|Stephen Paddock and his girlfriend|
Marilou Danley, 62, said Paddock, 64, 'would lie in bed, just moaning and screaming, "Oh my God,"' according to an ex-FBI official briefed on the situation.
Investigators - who interviewed Danley after she arrived back in the US from the Philippines on Tuesday night - believe that he may have been in 'mental or physical anguish,' that official and another ex-FBI source told NBC News.
However, they said that detectives are still no closer to determining Paddock's motive for the deranged shooting spree that saw him killing 59 people, including himself, and injuring 489 others.
While Danley's remarks suggest that Paddock was not well, investigators do not believe that his mind had deteriorated enough to set up and execute his elaborate mass-murder plan, which saw him firing on a crowd of 22,000 people at a country music festival.
Other areas now under investigation are the hour-long gap between 10:15pm, when Paddock unloaded more than 200 rounds into the hall outside his room, wounding a security guard, and 11:20pm, when police breached the room and found Paddock dead on the floor.
Paddock did not fire at all during that time. It was suggested by Las Vegas Sheriff Joseph Lombardo that he may have been trying to devise a way to escape.
At around 10pm Thursday, Valley Health System announced that eight victims were still in critical condition at its hospitals following the shooting. Valley Health system has six hospitals in Las Vegas and Nevada.
That was an improvement on Wednesday, when 58 were still in critical condition, according to the Las Vegas Review-Journal.
The count of injured people has been lowered from 527 to 489, Sheriff Joseph Lombardo said on Wednesday. The initial figure was accidentally inflated by hospitals in the confusion.
In a statement read out by her lawyer yesterday, Danley said she knew Paddock as a 'gentle' and 'quiet' man whom she loved and hoped to live a quiet life with.
She also said she had been oblivious to the violence he had been meticulously planning, and that she was out of the country during the attack because he'd bought her a surprise ticket to the Philippines - so, he said, she could visit her family.
Danley claimed that when he wired her $100,000 - ostensibly for her to buy a house for her family - she assumed that he was breaking up with her. She said she had no idea that he was planning violence.
On Thursday, Danley's brother in the Philippines, Reynaldo Bustos, 75, said that she had told him over the phone that her conscience 'is clear' over the killings.
In his native Tagalog, Bustos told ABC: 'I called her up immediately and she said, 'Relax, we shouldn't worry about it. I'll fix it. Do not panic. I have a clean conscience. I didn't have anything to do with this.'
Bustos and his family live in Village Park, an area where middle-class Filipino families' homes are built on lots which cost around $6,000. Danley arrived bearing gifts.
Bustos practices hilot, an ancient Filipino art of healing, and herbal medicine. He was not at home on Thursday and was treating a patient in Pampanga province, according to local sources.
He shares his home with his son Miguel and daughter-in-law Marizalyn Joy Bustos Waniwan. Along with Bustos' work as a faith healer, the family sells duck eggs and smoked fish.
'I saw a nice car parked on the street,' one neighbor told DailyMail.com. 'The next-door neighbor told me that it was Marilou.'
Danley is an Australian citizen who had renounced her Filipino citizenship, according to a local report by ABS-CBN. It is also not known precisely when she immigrated to Australia.
Her immigration status in the US has not been officially disclosed, but she married Geary Danley in 1990, and is likely to have qualified for a green card shortly after that.
A local told DailyMail.com that another of Danley's sisters, Dolly, owned land in a subdivision called Green Breeze.
Dolly is believed to live at a gated community, around 12 miles away, where homes start at around 3 million Philippine pesos or $60,000.
As well as speaking to Danley, investigators are also looking at 'six media devices' left behind by Paddock, and also exploring his web browsing history.
His web history also led to the discovery, announced Thursday, that he had apparently been scoping out other major events over the past year.
In August he booked a hotel room overlooking Lollapalooza in Chicago - the massively popular rock event that saw appearances by The Killers, Chance the Rapper and Muse, and that was visited by Malia Obama.
According to TMZ, Paddock - who lived in Nevada, 90 minutes from Las Vegas - booked two rooms at the Blackstone Hotel, overlooking Grant Park, where Lollapalooza has been held since 2005.
He made the booking using Expedia and insisted on a 'view room' that would overlook the festival, which ran on August 3-6, and also demanded he be notified in advance if such a room was unavailable.
However, officials said that he did not show up to the hotel for the booking.
He also researched possible locations in Boston online, according to multiple reports.
Anonymous officials said that Paddock looked for hotels near Fenway Park, where the Red Sox play and the Boston Center for the Arts.
It was not known if the gunman went as far as making any reservations, but an officer speaking to NBC News under condition of anonymity said that no hotels give a view over the park.
Via Daily Mail UK Receive Instant News Update Via BBM: D3EDEFDF...Click HERE for Details. Share your story with us: firstname.lastname@example.org PLACE YOUR TEXT ADVERT BELOW:>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> How I TOTALLY Got Rid Of my POT BELLY,excess Fat and Overweight In just 2weeks.. Click HERE for Details. Warning To Men: This 3 Foods Is Killing Your Erection. Click Here To Know Them