Officers in London’s Metropolitan Police are being investigated for potential misconduct after a 17-year-old-girl was killed by her abusive ex-partner despite reporting him to the police five times before her death.

The Times reports that Katerina Makunova was killed by 21-year-old Oluwaseyi Dada in Camberwell, south London, on 12 July of 2018. Makunova was visiting Dada at his apartment in order to retrieve a mobile phone he had taken from her. Police believe that Makunova was involved in a struggle with Dada, and fell onto a knife she’d concealed in her handbag. Dada pled guilty to manslaughter at Southwark Crown Court last week, and is currently awaiting sentencing.

Makunova’s family, however, told the Times that they believe that Dada should have faced a murder charge. “I am very, very angry,” her brother Julius told the publication. “I am appalled and ashamed at the way the Metropolitan Police has handled this case.”

In particular, her family believe that Dada’s history of controlling behavior, violence, and abuse should have been taken into consideration by prosecutors. Makunova was 15 when she met Dada on Instagram. She and her family called the police five times between February and June 2018 to report assault and harassment at his hands.

After her death, Julius looked through her phone and social media history, and spoke with her friends. He says that Dada once threw Makunova out of his flat naked, paid a friend to stalk her to see what she was doing, and sent pictures of her asleep in her underwear to other men. Julius also told The Times that he found a picture on Makunova’s phone of her bruised face after Dada allegedly attacked her.

Makunova also sent her threatening messages shortly before she arrived at his apartment on the day of her death. One said: “If u fuck about with a man mark my words all your family are [in serious trouble].” Julius claimed to the Times that Dada had previously made threats against his family. “Dada would tell her, ‘If you say anything to the police I am going to fuck up your family and your mother is going to be the first to get it’,” he said.