CHICAGO (CBS)– A former Chicago police officer Lowell Houser, 60, was found guilty of second-degree murder in the January, 2017 shooting of Jose Nieves.

This verdict comes almost a full three years after the deadly encounter.

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Prosecutors say in January of 2017, the then 58-year-old officer shot and killed Nieves outside of an apartment in Chicago’s Hermosa neighborhood.

The 38-year-old was unarmed.

Houser was off-duty and on medical leave for cancer treatment at the time.

He claims he pulled the trigger in self-defense after Nieves moved as if he was reaching for a weapon while the two were arguing.

Nieves’ sister Angelica talked about the loss of her brother and how it’s affecting their family.

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“I want it to be known that my family chain is broken, and it will never be the same. A piece of our family has been taken away from us,” she said. “It’s on his record … he murdered by brother that day.”

The sentencing came hours after another judge vacated Demetrius Johnson’s conviction for a 1991 murder investigated by former Chicago Police Detective Reynaldo Guevara.  Johnson’s lawer say he was framed. It is the 20th conviction tied to Guevara, who fabricated evidence in cases, that has been tossed.

Johnson spent 28 years in prison for a crime he didn’t do.  Yesterday, Demond Weston was released from prison after 29 years, for a murder he didn’t commit.  He was tortured by officers working for Cmdr. Jon Burge.

That’s three cases in one week, all tied to corruption by Chicago Police officers.

Angelica Nieves claims Houser also pulled a gun out on her brother a month before the deadly argument between them.

Houser now faces 20 years in prison.

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His is expected back in court on Jan. 24.