The loss of a child is a devastating event for any parent. However, when a human agency is involved in the child's death, the grieving experience for parents becomes even more complex. This study aims to conceptualize complicated grief in parents who have lost their children to homicide. This study employed a qualitative research methodology with a phenomenological approach. The target population of the study consisted of all women and men who had lost their children to homicide. Participants were selected through purposive sampling from courthouses and criminal courts in Gilan Province, Iran. Data saturation criteria were used to determine the sample size, and the Colaizzi's Seven-Step Method was used to analyze the data. The qualitative analysis of the interviews revealed three main themes (intrapersonal context, interpersonal context, and unknown context) and 45 subthemes. In addition to the challenges they experience in the intrapersonal and interpersonal contexts of homicide bereavement, bereaved parents also face a series of unfamiliar challenges in the unknown context of homicide bereavement. These unfamiliar challenges disrupt the healthy processing of grief-related emotions and make it difficult for them to fulfill their grief-related tasks.