Izabel Laxamana jumped from a bridge on May 29, just days after her dad Jeff cut off her hair and posted a video of the punishment online.
It has been reported locally that Izabel, from Tacoma, Washington, walked out of a car before jumping off a bridge onto Interstate 5 – the main highway on the US west coast.
She was taken to a Seattle hospital, where she died on Saturday.
Speculation is now growing about whether the 15-second video – which has been removed – led to Izabel's death.
Tacoma newspaper the New Tribune reported that the King County Medical Examiners’ office ruled the death as a suicide on Monday.
A spokesman for Tacoma Public Schools, where Izabel was a pupil, told the paper that counsellors met with staff at her school to help them support students after the girl’s death.
During the video, the girl can be seen looking into the camera as the lens pans to where her long dark locks lie scattered on the floor.
A male voice can be heard saying: “The consequences of getting messed up, man, you lost all that beautiful hair."
He then asks her: “Was it worth it?”
She replies "no" before he asks: “How many times did I warn you?”
She girl quietly replies: “A lot.”
It is still not clear why Izabel was in trouble with her father.
The News Tribune quotes reports on social media that the schoolgirl was upset after being banned from running for a position on the student body.
A statement said the girl did not have parental permission to participate as a candidate, and rumour-mongering was hurting efforts of students and staff to deal with the trauma of Izabel's death.
Blog Tacoma Stories claims that the public shaming could have led to Izabel's death and is a "form of abuse".
A post on the blog read: "There are those who will say that public shaming teaches a lesson. So does punching someone in the face. That doesn’t make it okay to do to your children.
"My thoughts are with this young girl. I hope that she gets the help she needs."
