It is not clear who the father of Mrs Halimi’s unborn child is.
Police have said she had been “staying at the home of a young Palestinian man from Nablus who she was in a relationship with”.
Officers added: “According to (Harouf’s) version, he met the deceased in the Holon area (in Israel), choked her, threw stones at her head, covered her body, and left the scene in her car in order to ‘release Palestinian prisoners’.
“Based on preliminary findings, including images and posts the two shared on Facebook, they intended to become engaged.
“As the investigation unfolded, the suspect was arrested and in the first stage of his interrogation contradictions arose regarding the whereabouts of the missing person – a fact that raised the suspicion of his involvement in her absence.”
The suspect has been arraigned on first-degree murder charges at Jerusalem Magistrates’ Court, according to the Jerusalem Post.
In recent days, Mrs Halimi’s widower denied Israeli police claims that his late wife had been in a relationship with Halouf and that the family would be filing a lawsuit against the force.