Fratricide comprises approximately 2% of all intra-familial homicides. Analyses of national data on fratricide show that adult males are considerably more likely to be offenders and victims or fratricide. A previous study suggested there were two main categories of fratricide: related to alcohol intoxication or associated with mental disorder.

Present and discuss the results of an original study comprising 28 cases of fratricide.

To provide up-to-date scientific knowledge on fratricide.

This is a retrospective study of 28 cases of fratricides, extracted from a sample of over 1000 consecutive cases of coroners’ files of victims of domestic homicide occurring between 1990–2015.

Two victims out of three were males, most of adult age. There were only 2 female offenders in the whole sample. A majority of victims were Caucasians while 21% were aboriginals. Most victims were stabbed to death. The murders usually occurred at the residence of the victim. In total, 39% of offenders suffered from a major mental illness; 21% were acutely intoxicated at the time. In victims, 29% were under the influence of alcohol and 18% of offenders were free from mental problems.

Our data indicates that fratricides are most often impulsive and lack preparation. The most common method was the opportunistic use of a knife, suggestive of impulsive killing, and this is consistent with the rest of the information including the high rate of alcohol use and intoxication at the time. The study confirmed two main categories of fratricide: impulsive killing in the context of alcohol and dispute and killing associated with psychosis.

The authors have not supplied their declaration of competing interest.