An online tribute to a teenage murder victim has been defaced, with internet trolls posting abusive messages and photos.

Chantelle Rowe, 16, and her parents, Andrew and Rose, were yesterday found dead in a house in Harriet Street at Kapunda, 76 kilometres north of Adelaide.

A Facebook page was set up for family and friends to leave messages of condolence, but it was quickly inundated with abusive message and doctored photos from profiles apparently set up in order to bait the victim's relatives.

Ash Booms-Davies was one of many who expressed her disgust at the trolls' actions.

"It makes me sick to think someone can say such horrible and disrespectful things about such a young girl who has been taken from the people who love her and she loves," she said.

"Put yourself in her family and friend's shoes. They have lost such a huge part of their lives and you are saying such things.

"Imagine if this happened to your family members and someone was saying such crude and hurtful things. How would you feel?

"It makes me sick. Clearly you don't deserve to be here."

But the trolls appeared unrepentant and other users cautioned irate commenters they were only playing into the trolls' hands.

'Sick new hobby'

"Please relax for just a moment - think about what it is he wants - then stop giving him the attention - ignoring him is all that is needed," Amanda Foxall wrote.

"It is called trolling, a sick new hobby for kids and adults who behave like kids."

The rise of social media tribute pages has been accompanied by a spate of online vandalism, including abuse and child pornography being posted on the sites of 12-year-old Brisbane boy Elliott Fletcher, who died after being stabbed at school, and Bundaberg girl Trinity Bates.

A woman from Queensland was also successfully prosecuted for posting offensive material on a Facebook tribute page for murdered Sunshine Coast woman Justine Jones.

Jessica Chantelle Cook, 22, pleaded guilty to posting hateful comments and photographs on a page set up in memory of Ms Jones.

Cook was released on two years' probation on the condition she not access any social networking sites and only use her computer for the purposes of email, employment and financial banking.

Queensland Police also launched an investigation into the pornography on Elliott Fletcher's page, but called for a wider debate within the community on dealing with the issue of online abuse.

South Australian police are not commenting on the Facebook abuse in relation to the Rowe family.

Investigation continues

Meanwhile, detectives are hunting for a knife and blood-stained clothing as they investigate the murders.

Police and State Emergency Service crews are focusing their search for clues in the immediate area near the house.

They say the trio were killed sometime between Sunday night and the early hours of Monday by at least one attacker.

The victims had multiple wounds.

Police are keen to work out the family's movements over the past weekend.

Teenage friends of the dead girl say they had attended a party at the house last Friday night and she was in good spirits.

They say Chantelle recently left Gawler High School to work at a cafe at Nuriootpa.