The specialist literature lists a number of characteristics of stalkers at high risk of assaulting their victims. These included substance abuse; a history of criminal offending, particularly violent and sexual offending; being male; making threats; having a personality disorder; pursuing an ex-intimate; and being unemployed. The current study examined whether these factors applied to perpetrators of serious, contrasted with minor, assault. The study sample consisted of 67 cases, all assessed by one forensic service in north London (England). For the purposes of this study, "stalking" was defined as "repetitive, multiple, unwanted intrusions or communications, which took place over a period of at least four weeks and which induced fear in the victim." In the study sample, violence against the victim occurred in 25 cases (37 percent). The violent cases consisted of 7 homicides, 11 serious woundings (mainly stabbings), and 7 lesser assaults (assault that caused "actual bodily harm"). There was no evidence of any association between serious violence and a history of substance abuse or substance abuse at the time of the offense. Seriously violent stalkers were found to be statistically less likely to have a criminal record and were less likely to be unemployed. They were not significantly more likely to have a personality disorder. Significant associations with serious violence were former sexual intimacy; going to the victim's home at an earlier stage in the stalking; earlier violence in the stalking, either to people or property; use of a greater number of types of stalking behavior; and a shorter period of pursuit.