Read more about this story from CNN affiliate KOMO.
(CNN) -- Investigators found the blood of Susan Powell, the mother of two who went missing in 2009, inside the family's Utah home and a handwritten will saying she feared for her life at the hands of her husband, court documents show.
The documents, unsealed late Friday, offer a glimpse of the evidence authorities collected that put Powell's husband at the center of the investigation into her December 2009, disappearance.
They also raise questions about why he was not arrested prior to killing himself and his two sons in a murder-suicide in February.
"If he had been in jail, our grandchildren would still be alive," Chuck Cox, the father of Susan Powell, told Seattle-based CNN affiliate KOMO.
Authorities say Josh Powell snatched the two boys -- Braden and Charlie -- from a social worker, who was delivering them for a supervised visit. He locked the doors and killed them and himself moments before his Puyallup, Washington, home exploded.
"Despite these events, Susan Powell is still missing. Her whereabouts, we haven't solved that yet. What happened to her, we still need to work on that," West Valley City Police Chief Thayle "Buzz" Nielsen told reporters, according to CNN affiliate KSL of Salt Lake City.
"My department is committed to locating Susan and bringing a resolution to this case. That's why it's still active."
The documents used as part of an affidavit to request a search warrant of Josh Powell's Washington home are also tied to a criminal case involving his father, Steven Powell.
Josh Powell maintained his innocence in his wife's disappearance until his death.
He had said he last saw her on December 6, 2009, after he and his two sons left after midnight to go camping in below-freezing weather in a desert area in Tooele County, Utah. Susan Powell's sister reported her missing.
A month later, Powell and his children moved from Utah to Washington where he moved in with his father.
But the documents paint a picture of a man uncooperative with authorities whose story about the night his wife disappeared changed several times.
They also reveal that one of the sons, Charlie, told a police investigator that "his mommy went camping with them, although she did not come back with them and he did not know why," the documents said.
Weeks later in Washington, Charlie told a teacher that "my mom is dead."
In the hours after Susan Powell was reported missing, authorities said they found two fans inside the living room sofa that appeared to have just been cleaned.
A search of the Powell home found "blood evidence was located on the tile floor next to the carpet adjacent to the sofa. Forensic tests of this blood indicated it was Susan Powell's," the documents said.
The documents also reveal authorities found Susan Powell's cell phone in the possession of Josh Powell. The phone was switched off and its portable memory chip, known as a SIM card, was missing, the documents said.
"We believe Josh intentionally removed that SIM card from the cell phone to intentionally thwart investigators," said West Valley City Police Sgt. Mike Powell, who is not related to the family.
He also later surrendered his cell phone to authorities, who say that phone also had its SIM card removed.
During the early days of the investigation, a detective located a safe deposit box that Susan Powell opened at a bank in Salt Lake City.
In the box, the detective found a letter that was folded and stapled around the edges. The letter was titled "Last Will & Testament for Susan Powell."
"This handwritten document indicates that she did not trust Josh Powell at all," Sgt. Powell said.
She wrote that her husband had "threatened to destroy her if they get divorced and her children will not have a mother and father," the documents said.
It also said, according to the documents, that "if Susan Powell dies it may not be an accident, even if it looks like one."
The documents also reveal that Susan Powell was terrified of her father-in-law, Steven Powell.
Authorities have said they discovered child pornography on the computer of Steven Powell. He was subsequently jailed and charged with 14 counts of voyeurism involving two child victims, and one count of possessing pictures of a minor engaged in sexually explicit conduct, according to court records.