He was walking through a track in the area of his house when he was approached by a man who shot him multiple times before fleeing the scene.
The 29-year-old singer ended her message by calling for an end to gun violence. "Love you man". She used the hashtag "#endgunviolence".
Rihanna also shared a video on Instagram showing Alleyne smiling and telling the camera, "It's nice to wake up and see all of your brothers and sisters". They were 23 gun-related murders past year. Almost 80 percent of murders a year ago were gun-related, according to Barbados Today.
Alleyne was rushed to the Queen Elizabeth Hospital by private vehicle, but succumbed to his injuries.
His sister, Tanella, also posted a photo of herself with Alleyne at the hospital, putting an emoji of an angel over his face.
Several of Rihanna's fans and friends sent their condolences after the post, offering prayers and support in her time of grief.
He had spent Christmas with his family, including cousin Rihanna, just hours earlier.
Tanella Alleyne's Instagram has been nothing but her baby brother Tavon Alleyne since his tragic death on Boxing Day.
Update: Shawayne Dashawn Williams was remanded after appearing before Magistrate Douglas Fredericks in the District "A" Magistrates' Court today.
Trump to attend Davos economic forum: White House
The president will "talk a lot about his economic program and the impact on the global economy", the secretary said. Moments before the White House announcement, one of those who will be going - Treasury Secretary Steven T.