THREE children were covered in blood and left wandering the street after their father allegedly stabbed their mother’s new boyfriend to death in front of them.

A senior police officer appeared close to tears when talking about the “traumatising” double stabbing in the southern Brisbane suburb of Alexandra Hill late on Tuesday night.

Inspector Rob Graham said the first responding officers arrived to a “horrific scene” when they arrived at the Brompton St address.

When they went inside a home they found two men “one dead the other almost dead”, Insp Graham said.

Police allege Osmond Greig, 39, forced his way into the home of his former wife and stabbed Daryl Corcoran a number of times with a “carving style” knife.

Mr Corcoran’s uncle, Stephen Corcoran, told the ABC he had two children of his own, aged 10 and 12.

“He’s left two beautiful kids behind. He was caring in everything he did; he’ll be sadly missed and much loved by the family.”

A friend, Phill Wadwell, described him as a “kind soul, very kind soul.”

Greig’s young children and former wife witnessed the stabbing, which happened in a bedroom.

“The person that’s died was in a new relationship with a 37-year-old female that lived at this address.”

The couple had recently started a relationship.

Police said Greig allegedly forced his way into the home by smashing a window at the back of the house.

“It will be alleged that the accused killer is the former husband of the female from this address,” Insp Graham said from the scene on Wednesday morning.

He then inflicted serious stab wounds on himself.

Inspector Graham said: “You can well imagine what the kids or the ex-partner have been through.”

The children spent the night at the home of a neighbour, Trish Kennedy.

“The kids are alright, they are tired, have been up since 11.30pm, but they are alright,” she told 7 News.

Another neighbour told the Today show she heard a man screaming, “Stay with your mother,” and then children’s voices before police and ambulances arrived that “lit the whole neighbourhood up”.

The family had only recently moved into the street.

Later on Wednesday, Detective Inspector Owen Elloy of the Bayside Criminal Investigations Branch described the scene as “confronting” and “traumatising”.

He appeared upset when speaking about the impact the incident would leave on the children.

“You have three young children — without a father figure — heading into Christmas, to my mind, is one of the most traumatising issues to hand.”

He said the children’s mother was deeply shocked but had provided an extensive statement to police.

Insp Elloy said the incident illustrated the need for people to take care of each other.

“We’ve got to give more thought to the people around us ... we have to look after each other more ... than what we have been in the past. The three children today will be remembered for all the wrong reasons.”

Greig was taken to Princess Alexandra Hospital for major surgery. He is under police guard in a serious but stable condition.

Police were hoping to hold a bedside hearing as soon as possible where they expected to charge the 39-year-old with murder.

Do you know more? Email: andrew.koubaridis@news.com.au

National domestic violence helpline: 1800 737 732 or 1800RESPECT. In an emergency call triple-zero.

andrew.koubaridis@news.com.au