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.

Prosecutors say the man charged in the stabbing deaths of four University of Idaho students​ bought a knife and sheath online in the months before the killings.

Prosecutors say they intend to introduce what appears to be a selfie Bryan Kohberger took on his phone just hours after the killings.

Mr. Kohberger has a right to present a full and complete defense for the crimes of which he is accused,” his defense wrote.