Everything I read stated or implied BK had a[nother] transformation after the murders. There were some reports that claimed him to be "chatty", except when the class talked about the murders; in which case he was quiet. But, for the most part, he started to let himself go, seemed preoccupied, grew out his facial hair, stopped leaving notes on the papers he graded, etc.
The criminology student said Kohberger's grading style took an abrupt turn after the murders took place.
abc7chicago.com
*edited to add link