An indictment seen by local media said the Israeli Arab family objected to her relationship with the man, who was serving time in prison, and intention to convert to Islam for him.
Their year-long relationship had sparked “vehement opposition” from relatives, whose threats allegedly forced her to flee her home in May and send messages to friend fearing “they are sending people to kill me”.
Police and social services had intervened in the case, summoning Henriette and her parents to a joint meeting on 11 June – two days before she was killed – and suggesting she enter a women’s shelter.
Officials said the teenager refused the offer and asked for help to rent a flat instead, returning to her parents’ home and attending a graduation party at her Jewish school the next day.
On 13 June, Henriette deposited 400 shekels (£86) into her boyfriend’s prison canteen account before returning home and telling a relative he would be released at the end of the week, and that she intended on converting to Islam.
Haaretz reported that the relative called Henriette’s father and told him of her plans.
She was found dead with stab wounds to the neck in the kitchen of her parents’ home in the town on Ramle on 13 June.
According to documents seen by the Jerusalem Post, the father believed Henriette’s actions “damaged the honour of the family and made him feel ashamed”.
“The defendant decided to cause the death of the deceased and in order to realise his goal he was equipped with a knife,” the indictment said.
“The defendant stabbed the deceased three times, causing her death on the spot.”
Lawyers representing Karra said he was not guilty and claimed the bad relationship between Henriette and her family was “no secret”, adding: “This did not lead to murder and could not lead to murder. The complaints against [Henriette] were only to reunite the family.”