Father and son killed in brawl at one-year-old's birthday party

Warning: This story contains the name and images of deceased Indigenous persons.

Police are searching for a group of guests who fled a one-year-old's birthday after a father and son were stabbed when a brawl involving up to 20 people broke out in Melbourne's south-east.

Emergency services were called to a property on Observatory Street in Clyde North about 9.30pm after reports of an altercation.

Police found 23-year-old Karl Gruber-Terrick and his 54-year-old father, also named Karl, with wounds investigators say were consistent with a stabbing.

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Police said the Seaford men were fatally wounded after an argument broke out that escalated into a brawl, which spilled onto the street.

Medical treatment was provided but they both died just metres from each other on the suburban nature strip.

"It's tragic. You can just imagine how that family is feeling now," Superintendent Janet Stevenson said.

"It should have been a great celebration, but it's just a dreadful ending.

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Detectives said multiple people left the scene before police arrived, including two men and a woman who neighbours saw run through a nearby carpark.

Police say they have identified the people who fled the scene early and urged them to contact police.

"These people hold the key, the people who have left early," she said.

"It's in the best interests, especially for this family, for them to contact us as soon as possible.

"And just don't drag this out."

Police have spoken to others who were present at the time and have searched the home, while the SES hunted for weapons that could have been left in bushes or on nearby roofs.

Detectives say a number of people are co operating.

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Meanwhile, tributes for the young footballer and his father have emerged, with the Fitzroy Stars Football and Netball Club remembering the 23-year-old as "a true gentlemen".

"We are grieving the sudden loss of one of our much loved playing members who was a true gentleman at our club, wore his heart on his sleeve and let his footy do the talking," the club said in a statement.

A friend of the young man described him as "someone I could always rely on" in an emotional online tribute.

"You were my brother, my rock," James O'Dwyer said in a post to Facebook.

"I will never forget our memories together that we shared..."

Neighbours detailed family members' desperate attempts to save the men.

"We just saw one man lying on the nature strip on the other side, and one on this side and there were two young people standing and shouting," a neighbour said.

"After a while the police gave the person CPR, and I think after maybe half an hour she was shouting 'my dad passed away'," another neighbour said.

"It was really devastating."

Anyone who witnessed the incident, with dashcam/CCTV footage or information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online.

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