Amid singer D4vd being locked up and currently fighting to keep his murder case from going to trial, his Apple Music page has been hacked ... posting a fake song with a voice sounding like the jailed artist professing his love for the victim Celeste Rivas.

The falsified track, titled "I DID IT" surfaced over the weekend, despite David Anthony Burke -- the artist known as D4vd -- remaining behind bars, without access to upload music himself. The track's artwork also features an aerial photo of D4vd's Tesla in the L.A. tow yard where Celeste's dismembered body was discovered last year.

The chorus repeatedly names Celeste ... describing her as "the girl with my name tattooed on her chest" and claiming her scent remains on his clothes "like cigarettes." The voice, mimicking D4vd's voice, also sings about hearing Celeste whenever he breathes ... missing her and fearing she will only love him after he dies.

The timing couldn't be more jarring as Burke remains jailed without bail as his preliminary hearing unfolds in Los Angeles ... detailing the gruesome evidence prosecutors have against the singer.

As TMZ has reported ... prosecutors spent the past week laying out evidence they claim connects D4vd to Celeste's killing, including messages revealing tension between the pair shortly before her death. The court also heard D4vd had "Celeste" tattooed on one of his fingers, while prosecutors say Celeste had his name inked on hers.

D4vd has pleaded not guilty to murder, continuous sexual abuse of a child under 14 and unlawful mutilation of human remains. The preliminary hearing will continue this week.

We've reached out to Apple Music and Burke's camp ... so far, no word back.