The state of California and the sanctuary city laws that make it a safe-haven for criminal illegal aliens is likely responsible for at least 5,000 crimes that were committed by criminal illegal aliens released by local authorities rather than being handed over to federal immigration officials.

According to data conducted for Breitbart News by the Center for Immigration Studies’ Director of Policy Jessica Vaughan, the state of California — which refuses to hand over criminal illegal aliens to the Immigration and Customs Enforcement (ICE) agency — makes up about half of all non-cooperation with federal immigration officials in the U.S.

For example, roughly 50 percent of the ICE detainers — the hold that federal immigration officials place on a criminal illegal alien — ignored by local sanctuary city authorities across the U.S. occurred in California.

In mid-2017, ICE Director Thomas Homan revealed that about 10,000 criminal illegal aliens had been released by sanctuary cities across the U.S. and went on to commit more crimes. This figure, though, could be even higher for the year of 2017.

Based on this data, Vaughan told Breitbart News that it is “reasonable to assume” that about half of those crimes committed by released criminal illegal aliens occurred in the state of California.

“That is 5,000 crimes that occurred that could have been prevented if they had cooperated with ICE as federal law provides,” Vaughan told Breitbart News. “What is the cost to Californians for that crime spree?”

“Surely it is a lot more than the cost of the few minutes of a California jail officer’s time to notify ICE, or to keep the offenders in custody for ICE for a few hours,” Vaughan said. “But California politicians like Gov. Brown, Xavier Becerra, and Libby Schaaf would rather have the crime, apparently.”

This estimate was gathered by provided ICE data, as the agency says it has no way of tracking the figure of how many exact criminal illegal aliens have been released into the public by California’s sanctuary laws.

“Lack of cooperation from sanctuary jurisdictions means that they do not notify ICE when they release an individual on whom we have filed a detainer, so we have no way of knowing exactly how many such individuals they have released,” an ICE official told Breitbart News. “We often become aware of an alien’s release from a jurisdiction when we re-encounter the alien later during targeted enforcement.”

As Breitbart News reported, Oakland Mayor Libby Schaaf recently warned criminal illegal aliens ahead of a regional raid by ICE, helping convicted illegal alien sex offenders, armed robbers, and drunk drivers escape deportation.

Attorney General Jeff Sessions’ Department of Justice is now investigating Schaaf for obstruction of justice. About 47 percent of likely voters say the DOJ should prosecute Schaaf for obstruction of justice, while only 36 percent of likely voters say the DOJ should not prosecute the mayor.

Sessions announced a DOJ lawsuit against the state of California, challenging three of its sanctuary state laws that protect criminal illegal aliens from deportation by ICE.