Authorities responded to a call that a student at South East High School was armed with a knife just before 11 a.m., and the school was placed on lockdown.
"We had a male student and a female student that became involved in an argument. During that argument, a dean tried to intervene, and in the process the dean realized that the male suspect had a knife and was attacking the female student," said Los Angeles Unified School District Police Chief Steve Zipperman. "Another male student tried to intervene as well. During that altercation, the female victim, the dean, and another student received injuries as a result of the knife."
"The girl who was stabbed by the student, her injuries are serious. I have been told officially that she is in stable condition, and the student who did the stabbing of course has been arrested and taken care of by the police," said LAUSD Superintendent John Deasy.
Five people were hospitalized. An LAUSD police officer said he suffered back injuries during the arrest, but was not stabbed.
The lockdown was lifted by 1 p.m.
The ex-girlfriend died at St. Francis Medical Center in Lynwood Friday night, according to the L.A. County Sheriff's Dept.
A bomb threat was reported at St. Francis Medical Center Friday night. The bomb threat was cleared later in the evening.
Preliminary reports earlier Friday indicated five people were stabbed.