Myrna Umanzor, 15, of San Leandro, was killed around 6:20 p.m. in the 1900 block of Pacific Avenue, San Leandro police said.
Responding officers found Umanzor suffering from multiple stab wounds to her torso and despite efforts by police and emergency medical personnel to save her, she died from her injuries.
Police suspect that Umanzor's boyfriend, 19-year-old Henry Leon, of Oakland, killed her and then took his own life the following day.
Leon was found hanged at the Port of Oakland on Saturday afternoon.
The two leave behind a 9-month-old baby.
Umanzor was a freshman at San Leandro High School. She had four younger brothers and one older brother, according to San Leandro Unified School District Superintendent Cindy Cathey.
Cathey described the mood at the campus as "somber."
"She had lots of friends," Cathey said. "It's a very sad time really for the school, for the children, and for the community."
She said there is free counseling support available for students and staff.
On Monday, a peace ceremony was held in honor of Umanzor where students released white balloons and shared memories of her, said Cathey.
She advised students who are in a relationship similar to Umanzor's to seek help.
"Go to a caring adult and talk about the situation," Cathey said. "They will help them get resources that are available in our community."
Students can reach out to their teachers, counselors, vice principal, or a supervisor on campus, Cathey said.
Dr. Elizabeth Miller, a researcher on teen dating violence at the University of Pittsburgh, said it is important for health care providers and parents to promote healthy relationships.
"The absence of an abusive relationship doesn't mean it's a healthy relationship," she said. "Parents need to... talk early, talk often about healthy relationships."
That conversation should begin as early as elementary school with a focus on defining appropriate language and how to be a good friend, Miller said. Parents can introduce the concept of a healthy relationship in middle school and discuss consent, sexuality and good communication in high school, Miller said.
She also advised young girls to seek help from their parents and other trusted adults if they see red flag behaviors by their partner.
"Abusive relationships can come in many different forms," said Sandi Goldstein, director of the California Adolescents Health Collaborative. Some of the common ones are controlling tendencies, such as a partner who constantly asks their significant other where they are or where they are going and who their friends are.
The abusive partner sends constant text messages and gets angry if their significant other does not respond right away.
The abusive partner demands to know their significant other's login and password information for social media sites.
Other signs are using degrading language, calling their significant other names and making fun of their appearance.
Physical abuse includes forcing their significant other to engage in sexual acts to which their significant other does not consent.
Goldstein said abuse also constitutes reproductive coercion and birth control sabotage, where a young woman is forced by her partner to have an abortion or have a baby against her will.
"Teen dating violence is associated with poor health outcomes for young people" such as increased suicide risk, depression, anxiety, unintended pregnancy, and sexually transmitted diseases including HIV, Miller said.
"As a community we need to recognize that adolescent relationship abuse is serious and can have devastating consequences," she said.
There are resources for teens that are in an unhealthy or abusive relationship. The National Dating Abuse Helpline at (866) 331-9474 provides assistance and support by peer advocates 24 hours a day, seven days a week.
Health care providers and school health centers can also help, as well as community centers such as the Davis Street Family Resource Center in Oakland and Girls Inc. of Alameda County.
Miller and Goldstein participated in a panel discussion in San Francisco today on teen dating violence as part of a campaign to raise awareness of abuse in teen relationships.
The campaign, which was launched to coincide with Teen Dating Violence Awareness Month in February, will feature ads on San Francisco Municipal Railway service buses, BART trains and station platforms, AC Transit buses and at the Westfield San Francisco shopping center.
Cathey said the San Leandro Unified School District is working with Umanzor's family to plan a memorial service. Information about the service will be posted on the school district website once available.
In the meantime, donations may be made to the Myrna Umanzor Memorial Fund at the Wells Fargo branch in downtown San Leandro. Checks may be delivered directly to the bank or any school in the district.