Interesting, pathetic, sad.
Before driving to Colorado Springs the killer started his spree at the Youth With A Mission (YWAM) base in Arvada (which is near Denver). He had previously been a Discipleship Training School (DTS) student there.
It takes some understanding of what a YWAM DTS is to realize the full betrayal of hospitality and love the killer committed. A DTS is 5-6 months in duration. The first 3-4 month phase is on-base, classes, counseling, and service. The service is both on-base (kitchen, janitorial, grounds-keeping) and in the nearby community (homeless shelters, community clean-up projects, etc. - the base near Chico probably recently sent volunteers to evacuation centers to help with people who escaped the Camp Fire). DTS students are not held captive or isolated in any sense - I visited my daughter during her DTS near Chico several times. Their weekends are largely free time, and DTS students visit the nearby town(s) and attend churches there.
The second phase is a 2 month outreach, usually to a country outside of the US. This is spent working with churches and local ministries, organizing activities, some construction work ... not touristy. Before sending a team out, the base and outreach leaders discuss, among other things, the suitability of each student. The killer had completed the on-base phase, but the decision was that he had shown himself to be unsuited for the outreach. He was sent home with his parents after that.
So, the people he killed at YWAM Arvada were people he knew, people he had spent several months with, people who had invested time and effort in trying to help him. That is the kind of ... well ... person DUpipo celebrated.
FWIW, my daughter's DTS outreach was to Fiji.