Rachel Kozloff allegedly killed Michael Henry, her boyfriend of eight months, after she "smelled sex" on him on April 12, say prosecutors.
Kozloff, who is currently on trial, denied killing Henry, but said he pushed her down some stairs at his apartment in Erie, Pennsylvania, reports the Erie Times-News.
Prosecutors say Kozloff shot Henry because she suspected him of cheating. Kozloff's 10-month-old son was in a nearby room.
Police never found the murder weapon, but found 9mm shells in Henry's apartment.
Prosecutors claim Kozloff bought a .40-caliber handgun and a kit to convert it to 9mm.