Violent struggle, and violent incident, would, in some respects, both apply. In the context of these murder, the police term of "violent incident" means homicide or attempted murder.
"Criminal Code incidents are sub-divided into four major groupings: (i) violent incidents, (ii) property incidents, (iii) other Criminal Code incidents (except traffic), and (iv) Criminal Code traffic incidents.
Violent incidents include offences that deal with the application, or threat of application, of force to a person. These include
homicide, attempted murder, various forms of sexual and non sexual assault, robbery, and abduction. Traffic incidents that result in death or injury are included under Criminal Code traffic incidents."
http://www23.statcan.gc.ca/imdb-bmdi/document/3302_D2_T9_V1-eng.pdf
http://www.eco.gov.yk.ca/fr/pdf/crimestats_95-03-l.pdf
Given that there was an attempted murder, or a homicide, one would hope that there was also a struggle where at least one of the three victims was able to struggle with the accused.