San Francisco’s "sanctuary" policies, which forbid cooperation with Immigration and Customs Enforcement (ICE), are preventing federal immigration authorities from interviewing the man suspected of attacking the husband of House Speaker Nancy Pelosi.

ICE sources told Fox News the San Francisco Sheriff’s Office has denied ICE officials the ability to interview David DePape, a Canadian illegal immigrant who is accused of attacking Paul Pelosi with a hammer at his California home.

An ICE spokesperson directed Fox to local officials for more details on the city's policies. San Francisco's Sheriff's Office (SFSO) confirmed to Fox News Digital that a person presenting as an immigration official arrived at the jail Oct. 31 with a business card and no government credentials and was denied access to the jail.

The Department of Homeland Security confirmed last week that DePape entered the U.S. legally across the U.S.-Mexican border on a visitors visa in 2008. He had come across on a B-2 visa, which typically allows Canadian visitors to stay for six months. He then allegedly overstayed that visa.

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DePape is pleading not guilty to charges of attempted murder, residential burglary, assault with a deadly weapon, elder abuse, false imprisonment of an elder and threats to a public official and her family.

An SFSO spokesperson said employees are not authorized to provide access or information to DHS and ICE employees conducting civil immigration enforcement, including access to inmates, computers, logs, arrest documents, release dates and home or work contact information.

"The policy of the San Francisco Sheriff’s Office is that we refuse ICE employees entry into the jail unless they present a criminal warrant," SFSO Director of Communications Tara Moriarty told Fox News Digital. "Our deputies do not grant ICE access to jail, and employees are not authorized to provide access to those who are conducting civil immigration enforcement."

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John Feere, a former ICE chief of staff during the Trump administration, said it was "standard practice" for ICE to interview jailed illegal immigrants to determine the next steps in the immigration case, and that this can provide ICE with important information.

"ICE is limited by what it can see in its files, and the person's circumstances may have changed since their last interaction with the federal government," he told Fox News Digital.

"When you're dealing with our electronic systems, ICE is seeing the fingerprints of an alien arrested by local law enforcement. But a face-to-face interview can confirm a lot of things. And the truth is, with any law enforcement situation, you never know what you're going to uncover during an interview" he said.

He also said it can uncover ties to other criminal activity.

"Officers learn a lot from the interviews of jailed aliens about how they entered the country or if they have left and reentered who they've been potentially working with, depending on the case," Feere said. 

But San Francisco is one of a number of jurisdictions that has "sanctuary" policies that forbid or limit cooperation with ICE. The state of California has also had sanctuary policies in place for years.

Proponents of sanctuary policies claim they reduce crime by encouraging otherwise law-abiding illegal immigrants to cooperate with police. Opponents say it merely protects criminal illegal immigrants from being deported.

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Specifically, San Francisco's sanctuary policies will prevent state and local law enforcement from honoring an ICE detainer, a request for law enforcement to hold illegal immigrants so ICE can transfer them into custody and put them into deportation proceedings.

DHS confirmed last week it had issued a detainer on DePape.

"[ICE] lodged an immigration detainer on Canadian national David DePape with San Francisco County Jail Nov. 1, following his Oct. 28 arrest," a DHS spokesperson told Fox News Digital.

The San Francisco Sheriff’s Office noted to Fox that the detainer would only be an issue if DePape is released from jail and said that whether that detainer would be honored is decided on a case-by-case basis.

"The sheriff reviews ICE requests on a case-by-case basis to determine whether informing ICE of Mr. DePape’s release date, if any, is consistent with our local sanctuary city ordinances," Moriarty said. "The sheriff will evaluate all information, up to the time of any release date, before making that decision."

However, San Francisco District Attorney Brooke Jenkins has taken a more direct approach.

"San Francisco is a sanctuary city, and our policy is sacred," she told the San Francisco Chronicle. "We will not be collaborating or coordinating with ICE."

To Feere and others who oppose sanctuary cities, the DePape case shows the problems with such policies and the risks to public safety involved.

"In the ideal world, this person would have been located, arrested and deported years ago," he said. "That's very difficult to do when you have localities that have no interest in working with ICE and do everything in their power to frustrate ICE's mission."

Fox News' Bill Melugin contributed to this report.

Research suggests that certain octopuses deliberately throw objects like silt, sand, and shells at other octopuses.

21 hours of film of Octupus tetricus, the common Sydney octopus, has captured over 100 instances of individuals gathering debris in their arms and then launching it away with a burst of water from their siphon — an organ octopuses also use to help them swim and steer.

While many of these “throws” appear to be used for cleaning out the octopuses’ den or chucking away shells, 53% of the 102 throws were made within two minutes of a previous interaction with another octopus, such as fighting, grappling, or even mating. About a third of those throws hit the other octopus. On a few occasions, one octopus would notice where the other was aiming and would duck out of the way.



“The throwing — or propelling, or projecting — of objects that have been gathered and held is rare in the animal kingdom. To propel an object, even for a short distance, under water is especially unusual, and also quite hard to do,” Professor Peter Godfrey-Smith, the primary author of the study, said.

Octopuses are generally solitary and territorial creatures and have even been known to cannibalize one another. However, they are exceptionally intelligent animals — they have an unusually high brain-body ratio, although their brains are dispersed throughout their arms rather than located solely in their heads. Octopuses are capable of using tools and engaging in complex problem solving — octopuses have even been known to escape aquariums, contorting their bodies so they can slip through even the smallest cracks; a 600 lb octopus can slip through a hole the size of a quarter.

Octopuses are also able to modify the shape, color, and texture of their bodies to a remarkable degree, often as camouflage to avoid predators or ambush prey. Some researchers believe this variation in color could also reflect variations in mood or function as a kind of social signaling.

“Earlier work at this site has found that darker colours are associated with more aggressive behaviours,” the team write. Octopuses that hit other octopuses with projectiles were usually darker in color than most were when performing a normal “throw”; they also tended to hold the projectile differently and throw it with more force, further suggesting that the strikes were deliberate.

Throwing behavior is rare, however — while individuals of both sexes were observed lobbing various objects, two females accounted for 66 of the 102 total throws.

Furthermore, despite the seemingly aggressive nature of the behavior, none of the strikes escalated to a full blown fight between the animals or provoked any “return fire.”

“I think quite a lot of it is a bit like an assertion of ‘personal space,’” Godfrey-Smith said. “In quite a few cases, females have thrown material at male octopuses who have been attempting to mate with them … But in other cases, females throw and hit other females.”

The footage was collected in Jervis Bay, off the coast of New South Wales, Australia, by stationary cameras.