MIAMI (CBSMiami) – The ex-wife of a South Florida man accused of murdering her new husband in a jealous rage in front of their twin children, testified in court Wednesday at a hearing to determine whether a Miami-Dade judge will dismiss the case based on the ‘Stand Your Ground’ law.

Cristobal Palacio is charged with murdering Paul Winter in 2008.

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When Palacio’s ex-wife Jennifer Winter took the stand, she recounted the horrific scene when her new husband was shot and killed.

“I screamed my head off,” testified Jennifer. “I remember watching him shot in the back. He was gasping for air. I tried doing CPR. I told him, ‘Baby, please don’t die.’ I could see the tears in his eyes. I tried to hold his hand and there was a shot through it. I started screaming for help.”

Jennifer told the judge that Palacio shot Paul in the back while their twins were in the car and when he was done, he stood smiling and grinning.

“He was standing next to the minivan toward the back window and he had a gun in his hand. He was hitting it against his thigh and smiling,” she testified.

She said the “children were huddled together watching in horror.”

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Then, she cried out to him.

“How could you do this? Why did you do this? How could you kill my husband?” she said she yelled at Palacio. He simply “smiled and grinned at me so proud of himself. No, he was happy. He looked happy,” recalled Jennifer.

At that point, she said, he walked back in the house and she called 911.

Winter was shot six times in Palacio’s yard. Paul and Jennifer went to the Kendall home to drop off his twin children for a court-ordered week of custody.

Palacio testified Tuesday that he felt threatened because he claims he saw Winter reaching for something he thought was a weapon. Winter was unarmed but Palacio testified Winter had previously pulled a gun on him.

Palacios claims he acted in self-defense and his attorney is attempting to get the case dropped under Florida’s “Stand Your Ground” law.

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The law states a person does not have to retreat in the face of a threat and can use deadly force if fearing danger of death or serious harm.