According to NY Post:
The victim, Kasandra Perkins, 22, and Jovan Belcher had a baby girl, Zoey, on Sept. 11. Her relatives declined comment to The Post. The tragic violence was allegedly set off after Belcher’s girlfriend was out late Friday attending a concert by R&B singer Trey Songz, according to the Wichita Eagle.
A friend of Kasandra Perkins, 22, told the paper that the couple argued when she returned from the show at The Midland. Belcher allegedly confronted Perkins when she returned home about 1 a.m. The couple, who met after being introduced by another Chiefs player, had dated about three years. They argued frequently, according to the source, who was not aware of any prior physical abuse, the paper reported.