JACKSONVILLE, Fla. -

A man convicted of killing a Sudanese refugee with a hammer during a September 2009 robbery was sentenced Thursday to life in prison without possibility of parole.

Merlin Williams Jr., 33, was convicted last month of first-degree murder, robbery and car theft in connection with the death of 37-year-old Isaac Siliman.

Siliman's family said he was a member of the Lost Boys of Sudan -- refugees who fled the civil war in their home country -- and had recently become a U.S. citizen.

Williams' girlfriend, 24-year-old Ashley Nichole Jerrell, had pleaded guilty and testified against Williams. She was sentenced to 25 years for second-degree murder, 25 years for armed robbery and five years for grand theft.

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"I wish I could take it back and replace my life with his, and I'm sorry, I'm so sorry," Jerrell told the judge while crying at her sentencing hearing Thursday.

Her attorney pointed out that Jerrell cooperated with investigators and took anger management classes, but it was not enough to lower her sentence.

Siliman was attacked with a hammer, stun gun and pepper spray, then his credit cards, computer and car were stolen.

Siliman had a wife and two children in Africa, one a baby boy he had never met. He was in the process of getting his family to America when he was killed.

George Loro, a friend of Siliman's who was at the hearing Thursday, said he thinks the sentencing will give the family some closure.

"I think the family back home will be relieved (with the sentences) for what they did to Isaac," Loro said. "I'm going to miss him, really. But this is how it ended."