A mum and her teenage son were found dead in their beds at home - but it's feared the reason why will never be known.
Jenny Smith, 37, and her son Joseph, 17, were discovered at their flat on February 22 this year.
Jenny was found under a duvet in the main bedroom while her son was found on a makeshift bed on the living room floor.
While toxicology tests showed the pair had both died from an overdose of fentanyl, a synthetic opioid 50 to 100 times stronger than morphine, an inquest into their deaths today found that a "piece of the jigsaw" appears to still be missing.
Coroner Anita Bhardwaj said the tragic deaths of both mother and son, who lived near Sefton Park, Liverpool, raised questions that would likely never be answered, the Echo reports.
"We don't know what has happened," said the coroner.
"There appears to be a piece of the jigsaw that is missing, that we are never going to know, and the only people who did know are Jenny and Joseph.
"There are so many unanswered questions."
Jenny, a former victim support worker, was last seen by a neighbour at around 10am on February 18 in the communal area of the flat block where she lived with her son.
Two days later, Jenny's father, Malcolm Smith, who lives in America, called Merseyside Police and asked them to check on his family, as he had not heard from them for several days.
Police visited the property on February 20 and 21, but nobody came to the door.
Phone calls to both Jenny and Joseph's mobile phones also went unanswered.
When officers returned at 11am on February 22 and found that a note they had posted to Jenny the previous day had not been touched.
They forced entry to the flat and found the bodies of both Jenny and Joseph.
"It was very much a shock to me that they had even touched anything like (fentanyl) because they were very much against drug use," said Malcolm.
"Jenny in particular was the kind of person who wouldn't take anything that wasn't prescribed to her.
"Jenny was quite happy-go-lucky; she enjoyed life. She didn't get out as much as she could because she suffered from gout.
"She did mix with people though, she wasn't a total loner.
"Joseph was exactly the same, very happy-go-lucky, very studious. He looked after his nan when she was not well.
"They were both good, ordinary people. It was a complete and utter shock to me that they should take fentanyl."
The court heard that no evidence of suspicious circumstances had been found either at the scene or during the post-mortem examinations.
Neither Jenny nor Joseph had any known history of drug use.
Jenny had previously suffered from psychotic episodes and Gilbert's syndrome.
"Joseph wanted to join the police force, then he wanted to do dog handling, then he thought about going into forensics, before he finally decided to go into computer coding," Malcom added.
"He absolutely loved video games, especially Grand Theft Auto, which they were both into in a big way.
"I can't imagine either of them to have ever experimented with drugs. It was very rare that either of them would take a drink.
"Joseph would have the odd one, a little glass of wine at Christmas. But neither of them were really into anything like that."
Delivering a narrative conclusion, Ms Bhardwaj said: "It's unclear as to why Jenny and her son consumed an excessive amount of the drug that was not prescribed to them."
Addressing Malcolm, she added: "They were clearly both intelligent young people and it must have been a shock to hear what had actually happened, and then when the toxicology came through, what the cause of death was.
"It seems such a loss of two young lives who clearly had future plans and a future ahead of them.
"I can only say there appears to be a piece of the jigsaw puzzle missing as to why they did what they did, but unfortunately we're never going to know the answer."
