Ferni Cristina Ayala Palacios, 28, posted the last picture with the caption “sweetheart” a few hours before she was found dead at her home in Buenos Aires, Argentina.
Authorities have identified her boyfriend, Esteban Rojas, 44, as the prime suspect in her death.
The woman’s sister Clara grew concerned after she couldn’t contact her and reported her as missing to the police.
Officers found the victim’s body in her home in the neighbourhood of Zavaleta with two bullet wounds to her chest.
Forensic experts said she had been dead for several hours.
Esteban, who had been dating the victim for around 18 months and lived with her for seven months, has since gone on the run, according to the police.
Ferni was allegedly shot dead in the early hours of February 19 after spending the evening at a bowling alley with Esteban and her two sisters.
The group went to the bowling alley to see a band Ferni liked.
She posted the tragic photo at around 2 am- just a couple of hours before she was killed.
The victim’s sister claimed she saw the couple arguing at the bowling alley and that Ferni got very upset.
Clara said: “We were never suspicious of him, but she did tell us he was a jealous person.”
“I never saw her with signs of violence. She distanced herself from the family when she went to live with him about seven months ago.”
She also claimed that Esteban’s ex-wife filed “three or four complaints” against him.
She alleged: “they say he threw his eight-month pregnant ex-wife down a flight of stairs. Later, that he violently cut a blonde girlfriend’s hair with a knife.”
Clara also said that Esteban is a moneylender who is very well-known in the area.
The authorities have issued a national and international arrest warrant against the suspect as the investigation continues.