An unidentified person sprayed gunfire into the 37-year-old's home as she and her children, who are 14, 16 and 18 years old, slept.
Janelle wrote on Twitter: "Gun violence has struck home. My beautiful 1st cousin was murdered. She was a mother of 3. Loved by her community. #NatashaHays #sayhername.
"Gun violence is still keeping our city in a dark place. The fear of 'who is next?' never leaves. Praying4more light. Help us.
"Nobody deserves to lose their mother, sister, cousin, friend, etc to the hands of evil. Evil has no race. Hearing your uncle on the phone while he tries to make sense of his daughter being murdered is the most helpless feeling in the entire world (sic)."
Natasha's kids were not harmed during the shooting and no arrests have been made by police at the time of writing.
As well as being a recording artist, Janelle campaigns against violence and last year released protest single Hell You Talmbout to honour victims of violence, including Eric Garner, who died after being put in a chokehold by a New York City Police Department officer. But a grand jury decided not to indict the officer.
What's more, Janelle has long been a supporter of the #sayhername and #sayhisname movement, which aims to humanise victims of violence.
This horrific incident comes after T-Pain's 23-year-old cousin Javona Glover, who had a two-year-old daughter, was stabbed to death in Tallahassee, Florida, earlier this week.
