The trial got underway on Tuesday for 43-year-old Thomas Prins, who is accused of beating and fatally strangling his girlfriend, 28-year-old Crystal Pifer last August.
"It's kind of hard not to think about it," said James Wagner.
Wagner, a key witness, took the stand and relived the night he said Pifer left Prins' boat and swam to his for help. He also called 911 and said she was hesitant to return to Prins' boat.
The state said the two spent the day arguing over their boat having mechanical problems, which later ended in Pifer's death. The defense said that is just an accusation and that Prins even called police after he couldn't find her.
Police said a fisherman found Pifer's body the next morning in the Halifax River.
Prins is charged with first degree murder and could face up to life in prison if convicted.