By Kristen Johanson

PHILADELPHIA (CBS) — It was swift verdict Tuesday in the trial of a Philadelphia man charged with the gruesome murder of a transgender woman 5-years-ago.

The jury took thirty minutes to convict 44-year-old Charles Sargent guilty of first degree murder for the 2013 stabbing and dismembering of Diamond William.

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Sargent told jurors he didn’t deny killing Williams, but said it was in self-defense after the pair got in a fight, when he said he realized the victim was anatomically a man.

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In her closing argument, prosecutor Kristen Kemp says Sargent had a chance to leave the house but went to get a screw driver instead, and then repeatedly stabbed Williams in the head.

“He murdered her, he dismembered her body, in the most despicable and egregious of manner,” she said.

Following the verdict, Sargent briefly apologized and repeated that he was only trying to defending himself in his home.

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Judge Diana Anhalt then sentenced him to life in prison, plus 6-12 years, and said that this was a trial she would never forget, and that she hopes to forget Sargent, but will always remember Williams.