Prosecutors say when Catherine Collins stabbed Boston Sicard in the heart, it was murder. Collins said she was defending herself.
A jury will have to decide how Sicard, 20, died in September 2010.
Prosecutors say Collins, now 22, went into the kitchen of her apartment to retrieve a knife, walked back outside and stabbed Sicard in the collarbone, near his heart.
Collins told police she and Sicard had argued over another woman who wasn't present. Collins said she shoved Sicard, who pounced on her, slammed her to the concrete and began choking her. Collins said she couldn't breathe for 30 to 50 seconds, the detective testified
Lawyers selected a jury Monday and prosecutors plan to begin presenting evidence this morning before Sedgwick County Judge Ben Burgess.