According to this REPORT, a Fairfax Police Officer was slashed by a suspect during a service call for a wellness check.  That wellness check was requested by the suspect's medical service provider.  The officer fired upon the suspect, killing her.  

Fairfax Police Chief Kevin Davis stated that the officer identified himself but that the suspect slammed the door in the officer's face. Thereafter, Davis explained when the suspect opened the door, she had a knife and began attacking the officer, cutting his face at least once.

We don't know the specifics of this incident but there's body camera footage. 

We're sorry to hear that the suspect lost her life.  It appears that someone was trying to get her help and something didn't go right.  We also hope the officer recovers.  We fight cops a lot, but only in court and not with knives.  

We don't pass judgment on what happened here.  It's just tragic.