The time marks exactly one year since constables Matthew Arnold, 26, and Rachel McCrow, 29, jumped a fence at a property at Wieambilla, west of Brisbane, before Nathaniel, Gareth and Stacey Train gunned them down in cold blood.

A year on from their heinous killings, emotions are still raw as the Arnold and McCrow families approach a second Christmas without their loved ones.

Const McCrow’s sister recently gave birth to a boy – a nephew she would never meet, while Const Arnold was a triplet and his family was still grappling with his death, Queensland Police Union President Ian Leavers said.

“That gut-wrenching pain, which all of us felt on that day, will never, ever be forgotten,” Leavers said.

“The way that they were callously executed in cold blood has resonated with every police officer in Queensland because they know it didn’t have to occur, it should never have occurred, but it could have been any one of them, just responding to a call for service.”

A year on from the killings, the police union is adamant it will one day acquire the Wieambilla property so it can never again “be used for evil”.

Neighbour Alan Dare was also shot dead before the Trains were killed in a gunfight with specialist police on the night of December 12 last year.

As well as the minute’s silence, some Queensland police stations plan to host morning teas on Tuesday to remember their fallen colleagues.

“Matthew and Rachel’s family … are in pain each and every day, and they do not want to publicly come out on the anniversary,” Leavers said.

“But they’ve asked me to convey the message, please never forget Matthew, never forget Rachel, don’t forget their families, but make sure that (we do) anything that we can do (to) prevent a tragedy like this happening into the future.

“Don’t let their deaths go in vain.”

The Arnold family released a statement saying December 12 marked a day of “incomprehensible evil”.

“We miss Matt’s laugh, kindness, empathy and willingness to help,” they said in a statement released by Queensland Police.

“These traits were what made him such an excellent police officer and made him love his job.”

The family also paid tribute to the bravery and courage of McCrow.

“We will forever stand with the McCrow family in the pain they feel with losing Rachel,” they said.

“We also remember Alan Dare on this day.”

Following years of concerns about gun-related crime around Australia, a meeting of federal, state and territory leaders last week agreed to establish a National Firearms Register within four years.

The agreement was reached on the day a US national was arrested by the FBI in connection with the Queensland attack.

Conspiracy theorist Daniel Day is accused of sending “Christian end of days ideology” to the Trains in the lead-up to the killings after they connected on YouTube.

After they killed the officers and Mr Dare, the Trains filmed a YouTube video during which they told “Don” they loved him and they would “be home soon”.