D4vd's Garage Had Possible Blood Stains All Over It, Forensic Criminalist Says

D4vd's garage was possibly covered in blood ... this according to a forensic criminalist who helped process his home.

Witness Lauren Wallace -- a criminalist with LAPD's forensic science division -- took the stand during Day 2 of the singer's preliminary hearing for the alleged murder of Celeste Rivas Wednesday ... and said red stains all over the singer's garage tested positive for possible blood.

Wallace was there processing the scene in September of 2025 days after Celeste's body was found, and said the team performed BLUESTAR tests -- used to find potential blood evidence -- inside the Hollywood Hills home D4vd was renting.

She testified stains near his Tesla charger and his rowing machine came back positive.

Wallace explained the floor was covered by black, rubber interlocking mats which had major damage -- including 7 linear cuts consistent with use of a sharp object -- and said the mats lit up to indicate possible blood during the BLUESTAR tests.

The team also processed a stained trash bag, and that also tested positive for possible blood ... and she said the inflatable pool found in the garage smelled like laundry, and had a dryer sheet rolled up inside of it.

Wallace added the mountain of evidence included a green tarp with red stains, disinfectant wipes and 2 chainsaws. However, she said the chainsaws came back negative for blood.

Deputy District Attorney Beth Silverman asked Wallace if they'd found a Makita 10-inch chainsaw -- the same one he allegedly ordered May 4, 2025 on Postmates -- and she said no.

D4vd appeared unfazed during the testimony ... just observing the evidence without any real reaction.

They went on break in the middle of Wallace's time on the stand, but Celeste's parents -- who'd been in court yesterday and today -- didn't come back when court reconvened.