An 11-year old girl was found dead inside her Wangaratta home on Sunday.

The death, which is being treated by police as suspicious, occurred after a party was thrown at the house – her mother’s – on Saturday night.

A 29-year-old man from nearby Mildura has been arrested and is in custody at a psychiatric unit of the Wangaratta Hospital.

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The man was picked up by police on an unrelated matter, after he was reported behaving erratically and walking along the Hume Highway at 6:00am on Sunday.

One neighbour said the party had wrapped up at around 2am.

Another neighbour heard screams and “wailing” coming from the house before police discovered the girl’s body at 10.55am on Sunday.

“I heard a terrible, terrifying scream, like someone wailing,” Jenelle Robinson told The Border Mail.

Locals leave flowers and toys outside the girl’s home. Photo: ABC

It is believed the young girl lived with her mother, whose boyfriend often visited.

Ms Robinson told The Border Mail her two young boys often played with the girl, and that parties were thrown at the house “probably every second weekend”.

Other neighbours told reporters they often saw the little girl playing with her dog in the street, or sitting on a letterbox.

Assistant Commissioner Rick Nugent said police were yet to speak with the arrested man.

“We do have a male in custody at the moment who police wish to speak to about this matter,” he said.

“The crime scene in Wangaratta will be processed by our crime scene specialists and homicide.

“There will be a number of witness statements taken from around the area.

“At some point in time, they will speak to the man in custody.”

Community in shock: ‘Everyone got along with her’

Jeremy Boruch said the community was shaken by the incident.

“She was a pretty quiet girl, but like most kids in the neighbourhood, most kids around here get along,” he said.

“I think the community as a whole might be under pressure. It’s one of those things that’s out of the blue.

“Not many people prepare for this sort of thing, do they? Shocking.”

His daughter Bonnie said there would be “a lot of tears” at the girl’s school and many would be devastated.

“She was a really nice girl and everyone got along with her,” she said.

-with ABC/AAP