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Thomas Sonnenberg, a 69-year-old retiree, liked helping others. So when a man appeared at the back door of his Minneapolis home just before noon on Friday screaming "Somebody's going to kill me!" and begging to be let inside, Sonnenberg did just that.

At the man's urging, Sonnenberg then dialed 911—but within moments, the man had shot Sonnenberg in the head, the Minneapolis Star Tribune reports. Police arrived 11 minutes after the call was made (the suspect had grabbed the phone from Sonnenberg to rant that a group was trying to kill his brother nearby, and gave police an incorrect address) to find Sonnenberg dead and the suspect, 20-year-old felon Devon Derrick Parker, still in the house, attacking Sonnenberg's wife.

Sonnenberg's daughter says she and her sisters had long feared for their parents' safety in a dangerous neighborhood—their home, which straddles the Camden-McKinley neighborhoods, had been burglarized in 2001, KSTP reports.

But the couple couldn't move due to an underwater mortgage. Sonnenberg did put keyed deadbolts on the doors, and his daughter says that's what ultimately allowed police to catch Parker: Sonnenberg made sure to lock the deadbolt after letting Parker inside, and the key to it was in his pocket, the St.

Paul Pioneer Press reports. Parker "went on a rage because he was locked in the house, and threw stuff at my mother and assaulted my mother," Sonnenberg's daughter says.

"He couldn’t get out of the house to get away." The family suspects Parker planned to rob the house, but police have not yet released a motive.

(Read about another act of kindness with a much less tragic ending here.)

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