Police say there are many reasons why someone may have wanted Scott Hammond dead and are not ruling out a revenge killing after he used his pit bull terriers to attack and wound four people in 2011.

Mr Hammond was found savagely beaten to death in his house on the outskirts of south-western Sydney along with a paralysed pit bull on Monday afternoon.

Police said they found the 48-year-old on the lounge room floor of an Ibbotson Street house at Tahmoor after a friend called concerned for his welfare.

Camden police Acting Superintendent Danny Doherty said homicide detectives were treating the death as a targeted attack and had many motives to sift through.

''It appears that the incident was a targeted attack and we have other motives that have to be looked at,'' Acting Superintendent Doherty said. ''There are a number of lines of inquiry including the man's history in relation to previous dog attacks.''