A substantial police presence in Oxford led to the sudden closure of Hollow Way Recreation Ground, prompting concern among nearby residents.
Officers began arriving on the evening of Sunday, November 8.
Fireworks and other noises continued late into the night, while many people in Horspath Road, Cowley, remained unaware of the police presence until Monday, November 9.
The Oxford park was inaccessible to the public and remained closed throughout the afternoon.
Police tape sealed each entrance, while numerous officers and police vehicles occupied the site.
Detectives in plain clothes were also present, speaking with potential witnesses and searching the grounds.
Adele Hearn and her partner, Tom Hearn, have lived in the area for 13 years.
Hearn said the situation made her anxious and that she disliked the thought of such a significant police response close to home.
She had also been irritated by the late fireworks but had given the matter little further thought until officers knocked on the door.
Jeff Cousins, 56, said the response left him feeling uncomfortable.
He had relocated from Dover two days earlier and questioned what was happening.
The police were informed about the incident early on Monday but had not provided a statement by 3.30pm.
Asma Ramzan, a resident of nearly six years, said the events made her uneasy.
She was asleep at the time, but her husband heard fireworks at the recreation ground and later spoke with officers after they arrived.
The Hearns described a large number of fireworks that sounded like a party, which they said was not unusual at that time of year.
The night in question coincided with Diwali.
Fireworks associated with Guy Fawkes or Bonfire Night had also featured in several other events during the preceding week.
A 45-year-old woman, who requested anonymity, said people had been setting off fireworks in the park after 10pm before police attended.
Although she considered the noise normal for an occasion of that kind, she said the scale of the police response was unusual.
After living there for more than 10 years, she had never seen the park cordoned off for such an extended period.
She described the neighbourhood as primarily family-oriented and said she was concerned.
The Hearns shared that concern.
A second anonymous resident, aged 38, described the response as crazy.
She regarded the area as pleasant, trusted the park and said she regularly walked through it.