In addition, Louis Ross "voiced some misgivings" about caring for a disabled child when he talked to officers investigating the child's Aug. 10 disappearance, according to a statement that Oakland police submitted to justify obtaining a search warrant of Ross' Fremont home.

According to the police account, Ross sent an expletive-laden text message July 31 to Jennifer Campbell, his fiancee and the aunt and foster mother of Hasanni.

"This is f- over, I will watch her but he will be out on the BART and its your responsibility to hey (sic) him so f- you," Ross texted at 9:50 a.m., police said. The references appear to be to Hasanni and his 1-year-old sister.

No trace of boy

Ross reported Aug. 10 that the boy had vanished from outside a shoe store on College Avenue in Oakland's Rockridge neighborhood where Campbell was working. Ross said he had briefly left the boy when he went around to the front of the store.

Police have searched the neighborhood, Ross' home, a Hayward auto wrecking yard that he visited earlier in the day and local parks, but have not found the boy.

A neighbor in Fremont told police that Hasanni had not been seen for about two weeks before Ross reported him missing.

Oakland police Officer Ross Tisdell wrote in the court papers that the relationship between Ross, 38, and Campbell, 33, "appeared to have some instances of domestic violence."

Police said they had heard reports of a "sword being brandished by Ross at Campbell," but did not elaborate.

A "sword or cutting instrument" were among the items that police sought in a search of his 2002 BMW and the home on Roxie Terrace in Fremont where Ross lives with Campbell and the two children.

Nothing was seized from the home, but Ross voluntarily gave his cell phone to police, court records show.

'Misgivings' about care

In talking to police, Ross "voiced some misgivings about caring for a developmentally disabled child," Tisdell wrote.

Ross says Hasanni wears arch-support braces because of his cerebral palsy, but that he can walk on his own.

Ross, reached by phone Thursday, downplayed any domestic disputes with Campbell. He said he had sent the text message in frustration at a time when he planned to break up with her.

"It was me venting about a situation in our past that had come back up," he said. "I was ending the relationship at that point."

Ross said he never left Hasanni alone at the BART station. He said he had wanted Campbell to pick up the children, but that she had been unable to do so. The dispute quickly cooled, Ross said.

Sword under mattress

As for the sword, Ross said he had told police about it and that officers had later returned and picked it up. He said he kept it under a mattress.

"It wasn't a big deal," he said.

Campbell, who is six months pregnant, has declined interview requests.

Ross has said he is cooperating with officials "100 percent" and that he told the truth when he took a polygraph examination last week.

John Burris, an attorney who has consulted with the couple, emphasized Thursday that Ross has always cooperated with the investigation.

"He's very responsive," Burris said.

The case has been puzzling to authorities, in part because bloodhounds could not detect Hasanni's scent outside the Rockridge shoe store where Ross says he left the boy.

In the search warrant affidavit, police said it was a mystery that Hasanni could disappear from "a crowded business district with no witnesses."

There is a $10,000 reward for information leading to the boy's whereabouts. Officer Jeff Thomason, an Oakland police spokesman, said the department still considers the case a missing person investigation. However, a homicide investigator has been put in charge of the probe.

E-mail the writers at hlee@sfchronicle.com and jvanderbeken@sfchronicle.com.

This article appeared on page A - 1 of the San Francisco Chronicle