Rifles, knives and a clown mask are believed to be among the items seized by police during a raid at a Derbyshire home which was attended by the bomb squad.
Officers carried out a search at a property on Godfrey Drive, Kirk Hallam, last Wednesday just after 9am.
Police said items had been recovered and were being examined, though no further details were released.
But eyewitnesses have revealed what they saw.
Cassandra Nelson said: “I watched as the police brought out a number of items from inside the house.
“There was what looked like a clown mask - it had a white smiling face and red cheeks.
“I also saw officers bring out what appeared to be a number of knives in plastic tubes. They were long knives.
“I watched as the officers also brought out what looked like two rifles in plastic evidence bags and I saw them bringing out computer equipment like hard drives.
“They were going in and out of the house for at least an hour-and-a-half and they were still doing that when I left the scene just before 4pm.”
Zak Meakin, 22, said: “I’ve been off work sick and have just seen it.
“There hasn’t been anything like this before around here so I’m really surprised.
“There’s usually only gangs of 14 or 15-year-olds pulling pranks, like throwing eggs, around here - nothing serious. The neighbourhood is usually a very nice place. It tends to be just elderly people and young families here.”
Another man, 33, who did not wish to be named, said: “I didn’t see anything till this morning, but then the police and bomb disposal came.
“The police arrived at about 9.15am and the bomb disposal men came at around 11am.
“I was really concerned because I have two kids that could be in danger. We weren’t informed about any potential danger or anything, which I think we should have really.
“We just saw bomb disposal members there, no evacuation message or anything. What if there was an actual bomb there? My first priority is making sure my kids are safe.”
After the incident a spokesman for Derbyshire police said: “Acting on information, police searched a house in Godfrey Drive, Kirk Hallam.
“The bomb disposal assisted us with this search and we have arrested a 44-year-old man.
“There is nothing to suggest the safety of the local community is at risk, or that this is a terrorist-related incident.
“Godfrey Drive was not closed and no one was evacuated.”
The 44-year-old man was arrested on suspicion of firearms offences and has since been released under investigation while inquiries continue.