Justice Williams was found hanging by a shower curtain in the bathroom. Her mother discovered her after she entered the room, wondering why she was taking so long.
Authorities were called to the Wallace Ave. home in the Bronx around 9:30 p.m. She was rushed to Jacobi Hospital where she was declared dead.
Her mother did not expect it, as she thought her daughter had overcome her depression over the new baby.
"We were as happy as happy could be until one day my then 8 year old woke up and decided that she wasn't exactly thrilled about being a big sister," Tamiqua Torres wrote on her personal blog. She often updated her blog about Justice's struggles.
Justice told family members that she "wanted to die" after she learned her mother was expecting. This was what prompted Tamiqua to find professional help for the girl.
The child was going to therapy regularly and seemed to be improving.
The new baby was born in August. Justice struggled with it as she was used to being the only child and never had to compete for attention from her mother.
Her family believed she was adjusted to the little brother because she assured everyone that she loved him and was happy.
"Fast forward to August when he arrived and she was happy and reassured that although her world has forever changed she loves him more than she thought she would. The road my family and I traveled to get to where we are now was not smooth, we faced many road bumps but over came them as a stronger family unit than I imagined us to be," Tamiqua said in a post written in January.
Justice was doing well in school and did not report any bullying.
People living in the apartment building were distraught after the ordeal, as tenants saw paramedics attempting to revive the girl.
"I just saw the mom and the baby. She was frantic. All you heard was them talking to each other, saying she was in cardiac arrest. She looked panicked. It looked like she did all her crying by the time we got here," Michael Millan, a boyfriend of one tenant, said. "The officers told us to move, get out of the way. Then we stayed inside until a cop knocked on our door."
Nelly Dominguez, a woman who lives across the street, saw the girl being transported into an ambulance.
"I saw them pushing on her heart," Dominguez recalled. "Oh my God, it's so sad. Then more detectives came and went in the house."
Police do not suspect foul play in her death and believe it was a suicide.
If it is ruled a suicide, she will become the second young girl to take her own life in the neighborhood in less than a year.
Last May, Wilnery Polanco-Uben, 11, took her life by hanging herself from a bedroom door. She sent suicidal texts to friends beforehand.
Suicide amongst children aged 10 to 14 is relatively rare, occurring in fewer than one in 100,000. The number rises in older teens and young adults.
In 2007 and 2008, no one under 15 committed suicide in the city.