Earlier in the investigation police arrested three other people on unrelated matters.
The men, aged 27, 30 and 30, have been charged with unlawful possession of a firearm.
Police cannot rule out the possibility that they will face further charges.
"Police would like to take this opportunity to thank the media and our community for the assistance they provided during our investigation," a spokeswoman said.
As the matter was now before the courts, police could not comment further.