[i]Thomas Sonnenberg was known for helping others. Friday, a man who asked for help killed him. The stranger ran to the back door of Thomas Sonnenberg’s north Minneapolis house, screaming “Let me in! Somebody’s going to kill me!” Sonnenberg, a 69-year-old retired technician known as a good Samaritan on his block, stepped outside, looked around and ushered the man inside, then was careful to lock the deadbolt. At the stranger’s behest, he called 911. Moments later, Sonnenberg lay on the floor, with a bullet to the head, and the man he had sought to shelter from harm was attacking Sonnenberg’s 68-year-old wife. Police arrived in time to interrupt the midday Friday assault in the small house in the 3700 block of Aldrich Avenue N., but they could do nothing for Sonnenberg, who died of the gunshot wound. The home invasion and killing, as recounted Saturday by one of the Sonnenbergs’ daughters and by police reports, was the fulfillment of the family’s fears about the dangers the retired couple faced in their longtime home on the ­border of the Camden-McKinley neighborhoods. Rachel Sonnenberg Baufield said Saturday that for years, she and her two sisters had begged their parents to move away from what they saw as an increasingly risky block. But the Sonnenbergs, who had endured burglary and vandals on their property, felt that they had no choice but to stay — they were trapped by an ­underwater mortgage. Still, Baufield said, her father had remained kindhearted, unable to turn away people who cried on his doorstep, including women who claimed they needed to leave town to escape abusive mates. “My dad has helped this community,” she said. “There have been other people who have come to my dad and begged for help, and my dad gave them money because he didn’t want people hurting. And this is the repayment that he gets.” Police arrested a 20-year-old felon with a ­violent history in the Sonnenberg slaying. Devon Derrick Parker of Minneapolis, who was on probation for a felony assault in 2011, was in the Hennepin County jail on Saturday on suspicion of murder, awaiting formal charges. Police have not yet disclosed a motive, but family members believe the attack was planned as a robbery...[/i]