OROVILLE, Calif. -

State investigators took the stand Friday to testify against an Oroville man accused of killing his pregnant girlfriend last June.

Olabaku Jones is charged with beating Abby Tucker to death, but Jones claims she had a seizure in the shower and fell.

A forensic blood analyst with the Department of Justice explained the crime scene for the jury step-by-step Friday afternoon. They claim to have found blood all over the bathroom, bedroom and other parts of the couple's home.

During the brief session, crime scene analyst Don Dunbar explained the trajectories of blood spattered around the house, on Spencer Avenue in Oroville June 24 .

Tucker was found naked on her bed with a towel covering the gashes on her head. Dunbar testified most of the blood spots found came from a downward movement that could be the result of a hand moving forward and backwards.

The blood found in the bathroom was diluted in some way and Dunbar said he found two nearly empty bottles of hydrogen peroxide. Dunbar said he smelled hydrogen peroxide on the towel Tucker had on her head.

They also discovered a bloody pillow and blankets inside the laundry room.

Dunbar said if Tucker was taking a shower that night the steam of the hot water might have played a role in the dilution.

The trial resumes on Monday and the prosecution expects Jones' son to take the stand.