A "massive bang" which puzzled people across South Yorkshire could have been caused by drug dealers.
Residents across the region were left scratching their heads last month after being awoken by huge early morning blast not far from Meadowhall shopping centre.
READ MORE: Early morning "massive bang" reported at Meadowhall
But one resident awoken by the noise now believes the noise was caused by drug dealers letting off fireworks - to alert "customers" that their drug supplies had arrived.
Twitter user Katrina Smith, who heard the original blast in the early hours of April 28, has since heard several other loud explosions at similar times and believes she has worked out the cause.
She tweeted: "Think I sussed it. Happening once a day lately. Local drug lord notifying customers his delivery is in - but at 5.15am!!!"
The huge blast was originally heard in the Rotherham and Meadowhall area and as far away as Saddleworth - 30 miles away on the other side of the Pennines.
There were no reports of fires or explosions in the area and Katrina added that the blast had woken, adding: "Asleep with ear plugs in! I expected to look out of window & see there'd been an explosion."
She said that she has heard the noise several times since and added: "Sounds like its quite close, especially to wake us up at 5am. Not every day but few days running last week at 7pm ish. I'm going to try and find out where it's coming from. It's not far."
She added that she thought the noise had been made "with one very loud firework. Not a rocket but a very big banger."
Fireworks have long been used by drug dealers to alert their clients that supplies are available to collect - although a lot of the reports are hearsay and unconfirmed by police.
It came just a few days before the "sonic boom" drama which rocked huge swathes of Yorkshire.
READ MORE: The night Doncaster was rocked by sonic booms from Typhoon fighter jets
On May 2, shortly after 9.45pm, people all over Doncaster reported hearing massive "explosions" - with many rushing into the streets and throwing open windows to investigate the noise.
Facebook and Twitter were awash with rumours - terrorist activity, a plane crash at Robin Hood airport, thunderstorms - but many others had heard military jets roaring through the skies and it soon became apparent that the noises were sonic booms, created by two of the RAF's Typhoon fighter jets going supersonic in the skies above South Yorkshire.
The aircraft were scrambled from RAF Coningsby in Lincolnshire to escort a wayward Air France airliner which had failed to maintain the necessary contact en route from Paris to Newcastle Airport.
The Ministry of Defence later confirmed the loud bangs were sonic booms.
And the incidents are not the first time South Yorkshire residents have been left puzzled by mysterious explosions.
Last October, residents in Long Sandall, Doncaster were left baffled by a massive late night noise with no obvious signs of what had caused the explosion or evidence of damage.
Andrew Hill said: “I felt the whole house shake and windows were rattling. “I went outside and could see smoke near the rail crossing but there were no obvious signs of what had happened.
“One of my neighbours said he thought his house was going to fall down it was shaking so much.
“No one seems to know what it was.”
And in November 2014, several loud 'mystery bangs' that shook windows baffled people across the country.
Dozens of Twitter users from London to Glasgow claimed to have heard the strange noises, which sounded like fireworks or loud aircraft.
Some suggested it sounded like 'aircraft sonic booms' and pointed to Russian airships that were performing 'routine military exercises' while passing through the English Channel.