collision was the first of the TCAS era

https://www.ainonline.com/aviation-news/aviation-international-news/2008-04-23/german-collision-was-first-tcas-era

only one controller working multiple flights on two radar scopes and two frequencies, the STCA was turned off and even the telephone was busy. 

 Man who killed air traffic controller he held responsible for death of family becomes father of twins

https://en.crimerussia.com/gromkie-dela/man-who-killed-air-traffic-controller-he-held-responsible-for-death-of-family-becomes-father-of-twin/