By Lori Fullbright, The News On 6

TULSA, OK -- Cori's Baker's family took the the witness stand on Monday afternoon in the murder trial of Marquis Bullock.  Bullock is accused of killing the 13-year-old girl in the fall of 2007.

Marquis Bullock was dating Cori Baker's oldest sister Courtney and they had a child together.  He lived with the Baker family for a time.

Testimony continues on Tuesday in Tulsa County District Court.

Cori's middle sister, Casey, testified that when she was 15, in 2005, Bullock wrote her a note, saying he was dreaming of being with her.  She said she later noticed someone had cut her blinds so they could look in her window and had drilled holes in her wall, so they could peek into her bedroom.

Casey said her father confronted Bullock about all of it and kicked him out of the house.

Tulsa County prosecutors are trying to show that after Casey rebuffed Bullock's attention, he turned his affection to Cori. 

The girls' father, Daniel Baker took the stand and went through some grueling questioning by Bullock's attorney.  She asked Baker about his boyfriend who lived in the house when Cori disappeared.  She asked whether Cori was afraid of the boyfriend or whether the boyfriend looked at child pornography on the family's computer.

Baker denied both.

The defense is hoping to show the jury someone other than Bullock posed a threat to Cori.  However, prosecutors say Cori was last seen alive with Bullock and no one else.