British millionaire jeweller Andrew Bush, 48, was found dead in April 2014 at his home in the Costa del Sol town of Estepona.
The suspect on trial for the murder is his ex-girlfriend, Slovakian model Mayka Kukucova, who is accused of shooting him dead when he returned to his home after a trip away with a new girlfriend.
When Bush, who ran several jewellery businesses in Bristol, and his new young sweetheart arrived at the house that night, they found Kukucova inside wearing pajamas. The new girlfriend, María Korotaeva, then went back outside to sit in the car, according to Diario SUR.
As Bush tried to calm his former lover, she reportedly shot him three times with a .38-calibre hand gun, twice in the head and once in the arm. She also reportedly placed the gun in Bush's hand and then fled in one of his cars, according to newspaper La Opinión de Málaga.
Korotaeva called police after seeing Kukucova run away and finding that she had been locked out of the house.
When police arrived, they found Bush dead from the gunshot wounds to his head. Authorities said at the time that they believed Kukucova had somehow let herself into the home and then waited for several days until he returned.
Kukucova fled to her home country of Slovakia, where she turned herself in.
The now 25-year-old model faces 20 years in prison for the alleged murder and stealing the car.
But her defense team has said that it was Bush who attacked her with the gun first and that it went off while they were struggling.
Korotaeva, a university student at the time, has posted tributes on Instagram to Bush since he was killed, saying she has tried to "stop hating" Kukucova for what happened.
"It was hard time for me. I had to stand up from my knees, stop crying, stop hating Maria Kukucova of murdering you," she wrote in a post a year and a half after Bush's death.
"[You] were in my thoughts and dreams for very long time... I guess, even now."
My Angel! My Love! My Boyfriend! you have left us 1 year 7 months ago It was hard time for me. I had to stand up from my knees, stop crying, stop hating Maria Kukucova of murdering you, not listening TV/ Radio and people, not reading newspapers and comments with it. I was on my final year when everything happened. Thanks god, that my family and friends were by my side. They were keep telling that I had to finish university and stay strong. Exams helped me to stay focused and don't loose my mind... The blood, lost fiancé, lost love, lost dreams with him, lost happiness and life purpose... were in my thoughts and dreams for very long time... I guess, even now