When police searched the home of a missing 5-year-old foster child in the days after his disappearance, they were looking for a "sword or cutting instrument" and biological evidence, the search warrant shows.
Hasanni Campbell , who lives with his foster father and his aunt in Fremont, has been missing for 10 days. Police did not take anything from his house during the search, the Oakland Tribune reported.
NBC Bay Area learned Thursday that Ross failed a polygraph test given by police last week.
Ross reported the boy missing from the parking lot of the Shuz of Rockridge shoe store in the 6000 block of College Avenue in Oakland about 4:15 p.m. 10 days ago.
Court documents obtained by NBC Bay Area's Jodi Hernandez show even more disturbing details about the couple's relationship.
According to the investigators, text messages on Ross's cell phone point to instances of domestic violence.
In the documents, officer Ross Tisdell stated: "On 31JUL09, at about 0950hrs, Ross sent an outgoing message to Jennifer Campbell, the boy's aunt. The text message read, "This is f*#king over, I will watch her but he will be out on the BART and its your responsibility to (sic?) get him so f*#k you."
The court document also said a sword was once brandished by Ross at Jennifer Campbell. It was unclear whether this information came from a text or a police interview.
Two investigators in the case said Ross admitted that he left Hasanni and his one-year-old sister alone in the home while he went to the bank. He also told investigators he had "misgivings about caring for a developmentally disabled child" during the interview.
Investigators searched Ross's car shortly after they started the investigation and recovered a pair of latex gloves, eight DNA swabs and fingerprints. They towed the car the first night.
Jennifer Campbell is pregnant and said she did not want to take the polygraph test because she was concerned it could harm her unborn child. Ross and Campbell are engaged.
Thomason said police talk to Hasanni's foster parents everyday and that they are being cooperative.
On Monday, Ross addressed speculation that he might be involved in Hasanni's disappearance. He told reporters to talk to social services about the placement of Hasanni in his home.
“You go to them and ask them why they placed them with us. Because we gave a damn! These were our children," Ross said. "Don't try to take that from us. This wasn't a situation where we didn't care about those children. We've fought every inch for both of them."
The couple was also serving as foster parents to Hasanni's younger sister, who has been taken from the couple.
A reporter for Oakland TV station KTVU asked Hasanni's grandmother on Monday if she thought Ross had anything to do with the disappearance. She said no, adding that she trusted Ross completely. She told Jodi Hernandez the same thing Wednesday saying, "It was a stranger" that took Hasanni.
Thomason said police are still treating Hasanni's disappearance as a missing-persons case and that there is no evidence a crime has been committed.
"We're asking the public to call if they have any credible tips," Thomason said.
Police said they have followed up on all of the approximately 50 tips they've received so far but none have panned out. Thomason has told reporters that 50 is a very low number when it comes to high-profile cases like Hasanni's. They normally come in by the hundreds.
Police describe Hasanni as a black boy with medium complexion, brown hair and brown eyes. He is about 3 feet tall and weighs about 30 pounds. He was last seen wearing a gray sweatshirt and gray pants.
Oakland police and Crime Stoppers are offering a $10,000 reward for information leading to the whereabouts of Hasanni.
Bay City News contributed to this report.