The sisters of slain police officer Neal Thompson, who was shot dead last year by Dezi Freeman, plan to sue Victoria Police over his death.

Lawyers for Dianne Thompson and Lois Kirk have confirmed they intend to take legal action following the death of their brother last year.

The legal action relates to specialist forces not being deployed to execute a search warrant at Freeman’s property at Porepunkah on August 26.

Detective Leading Senior Constable Thompson and Senior Constable Vadim De Waart-Hottart were killed by Freeman, and a third officer was injured before the self-proclaimed sovereign citizen disappeared into dense bushland, sparking Australia’s largest-ever tactical police operation.

That operation ended with the fatal shooting of Freeman at Thologolong, in Victoria’s north-east on Monday, after a three-hour stand-off with police.

The legal action comes after the sisters of Mr Thompson expressed disappointment late last year over their treatment by Victoria Police.

Ms Kirk and Ms Thompson wrote to Chief Commissioner Mike Bush in December, saying they felt “abandoned” by Victoria Police in the wake of their brother’s death.

In the letter, seen by the ABC, the sisters said they were made to feel “invisible” by police.

“From the moment we were informed of Neal’s death by a phone call instead of in person, it felt as though the magnitude of the loss had not been understood. Something so final, so life-breaking, deserved presence, humanity, and care,” they said.

“Instead, we were left alone in a room with news that shattered us. No support arrived, no face we could speak to, no hand on our shoulder. Only silence.”

Ms Kirk and Ms Thompson said they were disappointed with how relatives were treated at their brother’s funeral, with some having to stand “while others with no close connection were prioritised”.

“We had to approach the Prime Minister and the Premier ourselves as they did not know who we were,” they said.

“They were not going to come over to acknowledge us. To be ignored like that during our brother’s Full Police Honors funeral was painful beyond words.”

A spokesperson for Victoria Police said police had met with the sisters since the letter was sent in December.

“We are continuing to speak with them and they have appointed police liaison officers, both from the Homicide Squad and the local area. This is to ensure they are updated on the investigation and to also provide further support with regards to their welfare and events such as memorials,” the spokesperson said.

“While every effort is made to provide timely updates to all families involved, we are always conscious of the need to manage ongoing investigations.

“Again, we acknowledge that this remains an exceptionally difficult time for all the families involved and we will continue to speak with them and address any ongoing concerns they have.”