A flurry of court filings in the quadruple murder case against Bryan Kohberger reveal the suspect bought a knife on Amazon months before the killings and the victims’ surviving roommates texted family and were active on social media before calling 911.

Attorneys working to present their case in the murder trial of Bryan Kohberger this summer are zeroing in on the timeframe before and after four University of Idaho students were slain in an ambitious effort to convince a judge to discard or allow certain evidence.