A tip from the Democratic mayor of Oakland, Calif., may have helped illegal immigrants convicted of crimes evade law enforcement, further endangering their communities.

After Mayor Libby Schaaf got word of an impending Immigration and Customs Enforcement raid in the Bay Area, she tweeted a warning to help potential targets of the operation prepare. "I know that Oakland is a city of law-abiding immigrants and families who deserve to live free from the constant threat of arrest and deportation," Schaaf said at the time. "I believe it is my duty and moral obligation as mayor to give those families fair warning when that threat appears imminent."

But as Schaaf well knows, her tip to "law-abiding" immigrants was public, meaning every potential target of the raid had access to the information. According to ICE, the operation was specifically aimed at capturing "public safety threats." Thus, by announcing the raid, Schaaf theoretically helped public safety threats remain in her community or escape to other communities.

And that's exactly what ICE says happened. "What she did is no better than a gang lookout yelling 'police' when a police cruiser comes in the neighborhood, except she did it to an entire community. This is beyond the pale," acting ICE Director Tom Homan said on Fox News, contending that Schaaf "absolutely" hurt his agency's enforcement effort.

According to ICE, while the raid targeted roughly 1,000 people, it led to the arrests of 232 illegal immigrants, 180 of which “were either convicted criminals, had been issued a final order of removal and failed to depart the United States, or had been previously removed." One-hundred-and-fifteen of those arrested "had prior felony convictions for serious or violent offenses, such as child sex crimes, weapons charges and assault, or had past convictions for significant or multiple misdemeanors."

The New York Times reported last week that "one official briefed on the plans for the operation at the Department of Homeland Security, which includes ICE, said that ICE agents typically find only about 30 percent of their targets during any large sweep," suggesting the raid underperformed.

An ICE spokesperson provided examples of several targets that evaded capture in the operation to Fox News:

One Mexican citizen had convictions for unlawful sexual intercourse with a minor and a conviction for driving under the influence (DUI), and had been deported in 2003.

Another who evaded capture had a conviction for sodomizing a drugged victim in 2012, as well as a DUI from this year — that Mexican citizen had also been previously deported in 2013.

Another illegal immigrant from Mexico, previously deported in 2014 for a conviction for armed robbery, also evaded capture.

Whether or not Schaaf's warning helped these three people in particular is impossible to say, but there is absolutely no question it could have.

Speaking at a news conference on Wednesday, Attorney General Jeff Session addressed the mayor directly. "So here’s my message to Mayor Schaaf: How dare you? How dare you needlessly endanger the lives of law enforcement just to promote a radical open borders agenda?"

As the mayor of one of California's largest cities, Schaaf is familiar with ICE's operations, and knew her warning to the illegal immigrant community at large would cause likely targets, including people with criminal convictions, to flee or hide, keeping them in her city or sending them to others. She sacrificed their potential captures to promote her agenda. As Homan pointed out, the mayor also endangered the lives of law enforcement officials tasked with conducting the operation.

If Schaaf wishes to protect "law-abiding" illegal immigrants, that's one thing. But to help threats to her constituents' safety evade arrest is another.