70s movie where a girl sleeps with her teacher and kills

A headstrong young teacher in a private school in 1930s Edinburgh ignores the curriculum and influences her impressionable 12-year-old charges with her over-romanticized worldview.

Muriel Spark's classic novel The Prime of Miss Jean Brodie was adapted by Scottish Television into a seven episode television serial for ITV in 1978 that featured Geraldine McEwan in the lead role. From Wikipedia.

When a university student refuses to sleep with her professor in exchange for good grades, she's in danger of being killed to keep her quiet, and her mother must drop everything to save her.

New school headmaster and single mother Kathy discovers her vacation fling with charming 18-year-old Ian was no accident when he transfers to her school targeting Kathy and her teenage daughter Bree in a deadly scheme. Ian wants revenge as he believes Kathy is responsible for splitting up his family ultimately leading to his father's death. Kathy will need to uncover Ian's motives quickly if she hopes to protect herself and Bree from his dangerous threats.

A male high school student becomes obsessed with his teacher and uses various schemes including exposing her philandering husband to have sex with her.

A high school substitute English teacher resorts to murder to protect her murderous dark past while seducing a student who begins to suspect her true identity.

Strict teachers, all those hours inside four walls, all your desires and youthful energy repressed. School is an endless drag - until she comes along. Uhm Ji Young has a perfect body and metric tons of sex appeal, and she knows it. Needless to say, all the students go crazy, and the male teachers too! They should be preparing for the annual school festival, but they're all occupied with other matters.

Successful teacher and author Charlotte Hansen has a passionate, one-night stand with a younger man, Chris. She later finds out that he is 18 years old and a student at her high school. Now, Chris will stop at nothing to have her for himself.

A deceptively innocent high school teacher forms a toxic relationship with one of his female students, who must outwit his sociopathy in order to graduate high school alive.