Law enforcement officials work the scene of the Texas church shooting. Photo: Eric Gay / AP

Law enforcement officials investigating the mass shooting at the First Baptist Church in Sutherland Springs, Texas, said they have not yet been able to get into suspect Devin Kelley's phone. The phone was flown to FBI headquarters in Quantico, Virginia, on Monday for further tests.

Why it matters: Kelley's phone may contain key details about his motives. Authorities said Monday that Kelley was engaged in "a domestic situation" with his in-laws. He reportedly sent angry messages to his mother-in-law before the attack on the church, and his grandmother-in-law was among the people he gunned down.

This isn't the first time FBI investigators have had difficulty breaking through encryption to access information on phones. Deputy Attorney General Rod Rosenstein said, "Warrant-proof encryption is a serious problem ... When investigations of violent criminal organizations come to a halt because we cannot access a phone, even with a court order, lives may be lost" in a speech at the U.S. Naval Academy.

After the San Bernadino shooting, the FBI called on Apple to help unlock one of the shooter's phones for the investigation. In a memo to Apple employees, CEO Tim Cook said helping the FBI get into the shooter's phone could set a precedent that "threatens everyone's civil liberties" and he called on the government to withdraw its request. The FBI eventually accessed information inside the phone with help from an outside group, per the Washington Post.

"We will get into that phone," Christopher Combs of the FBI said Tuesday, referring to the Texas shooting investigation.

Go deeper: Full coverage of the shooting and its aftermath

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Updated 20 mins ago - Politics & Policy

Tim Scott says Trump "misspoke" when he told Proud Boys to "stand by"

Photo: Bonnie Cash/Pool/AFP via Getty Images

Sen. Tim Scott (R-S.C.) told reporters on Wednesday that he believes President Trump "misspoke" when he told the far-right "Proud Boys" group to "stand back and stand by" in response to a question about condemning white supremacy at the first presidential debate.

Catch up quick: Moderator Chris Wallace asked Trump on Tuesday, "Are you willing, tonight, to condemn white supremacists and militia groups and to say that they need to stand down?" Trump asked who specifically he should condemn, and then responded, "Proud Boys, stand back and stand by. But I'll tell you what, somebody's got to do something about antifa and the left."

Updated 28 mins ago - Politics & Policy

Commission on Presidential Debates wants changes

Photos: Jim Watson and Saul Loeb/AFP via Getty Images

The Commission on Presidential Debates announced Wednesday that it plans to implement changes to rules for the remaining debates, after Tuesday night's head-to-head between Joe Biden and Donald Trump was practically incoherent for most of the night.

What they are saying: "Last night's debate made clear that additional structure should be added to the format of the remaining debates to ensure a more orderly discussion of the issues," the CPD said in a statement.

Trump says he doesn't know who Proud Boys are after telling them to "stand by"

President Trump told reporters on Wednesday that he doesn't know who the "Proud Boys" are, after saying at the presidential debate last night that the far-right group should "stand back and stand by" in response to a question asking him to condemn white supremacists.

Why it matters: The comments set off outrage and calls for clarification from a number of Republican senators. After being asked several times on Wednesday whether he will condemn white supremacy, Trump responded: "I have always denounced any form — any form of any of that, you have to denounce. But I also — Joe Biden has to say something about antifa."