There's a different kind of depth to the darkness at nighttime in the upscale Catalina Foothills neighbourhood of Tucson, Arizona. Lights are limited by both the county and the homeowners' association; they must be shielded and can only face down, a deliberate effort to maintain Tucson's 'dark sky' status - designed to minimise light pollution, reduce energy waste and protect astronomical research at nearby facilities. The result is a quiet, peaceful blackness making Catalina Foothills the perfect spot for stargazing - or for furtive criminal activities like kidnapping an elderly woman. This was reported by Qazaqyia.kz citing BBC News.

That's what happened overnight on 31 January, when 84-year-old Nancy Guthrie, mother of US television presenter Savannah, was pulled from her bed. The assailant - or assailants - vanished into the 'dark sky' night with the church-going grandmother. This was reported by Qazaqyia.kz citing BBC News.

And the case ever since has been nearly as obscured as the Catalina Foothills after nightfall - beset by everything from tricky terrain to law enforcement infighting. The list of challenges facing the investigation into Nancy Guthrie's disappearance goes on and on - and perhaps goes some way toward explaining why answers remain elusive nearly five months after the 84-year-old was abducted from her Arizona home.

The lack of resolution, with no suspects identified and no information as to where Guthrie was taken, is all the more perplexing given the spotlight that's been on the case from the outset thanks to the celebrity of Guthrie's daughter, famous US news presenter Savannah.

Law enforcement consultants, media and citizen sleuths have been poring over the case with no success - and details made public this week from ransom notes raise only more questions. The Guthrie family believes the notes, received in the days after the crime, to be real. One of them allegedly demanded millions in bitcoin, the second allegedly said she had died, while expressing regret on the part of the writer.

And the simple possibility of a kidnapping gone awry could be one explanation for why the case seems stalled, according to experts - though the Pima County Sheriff's Department says it remains 'active and ongoing.' If Guthrie died during the crime, says private investigator Dan Ribacoff, 'now it's a murder and not just a kidnapping.' 'It probably drove the criminal underground,' said Ribacoff, who founded the International Investigative Group and has dealt extensively with kidnappings and missing persons cases throughout his career. 'He doesn't want to release … where the body is buried, because he doesn't want to expose himself,' said Ribacoff, who agrees with the Guthries that the notes could be genuine.

If the kidnapping had gone according to plan, he says, there'd likely be a better chance of a happier ending - and even arrests. 'I believe that a ransom would have been paid, she probably would have been released, causing additional leads to be generated - maybe through IP addresses or telephone records, things along those lines, but it went cold very, very quickly evidence-wise right after that kidnapping.'

And evidentiary issues have plagued the case from the start for a variety of reasons, according to law enforcement experts. Not only are the Catalina Foothills area incredibly dark at night, but the region is also filled with terrain that makes it easy to hide - and hard to find evidence. 'The Tucson Valley, if you look at it, it's rimmed by four mountain ranges, and they're pretty rugged, and the Catalinas are the most rugged - and [Guthrie's house is] right at the base of the Catalinas,' says consultant David Smith, who spent 17 years in Arizona law enforcement, including time as a police officer in Tucson - the location of the home from which Guthrie was taken. 'The terrain is such that it's difficult to see the actual roadway,' he said. 'If you look at the aerial view of her property, you could actually pull in the driveway and not ever be on her Ring camera.'

The neighbourhood is filled with dry watercourses called arroyos that 'go right up to people's backyards, and very often the criminal element would use those to get around - and so would the innocent,' said Smith, who's walked the area around Guthrie's house and personally witnessed the foot traffic. On top of that, he said, the evidence is 'transitory' because of the weather. 'Frankly, there's so much traffic, it's hard to pick out footprints, those types of things,' he said. 'That's the geographic challenge.'

On a wider scale, Tucson presents several criminal challenges because of its proximity to an international border, its high homeless and crime rates and its high drug use, he said. On top of that, local vs federal feuds have complicated the investigative effort. Pima County Sheriff Chris Nanos has repeatedly insisted that he involved the FBI immediately, including working with a liaison on site the night of the kidnapping. But FBI Director Kash Patel has criticised the county's actions, stating in a May podcast interview that his agency was 'kept out of the investigation' for 'four days.' Patel also claimed that local authorities rebuffed FBI offers to fly DNA evidence to the agency's lab at Quantico, instead choosing a private lab in Florida.