The trial of a Norridgewock man accused of fatally shooting an Anson man in a drug dispute began Monday morning.During opening statements at 41-year-old Robert Nelson’s murder trial, prosecutors and defense attorneys agreed on one thing: The victim, 60-year-old Everett Cameron, was shot over drugs. What they don’t agree on is who pulled the trigger. During his opening statement, Assistant Attorney General Donald Macomber says it was Nelson whose addiction to prescription pain killers was so acute he did the unthinkable. “Some people are so desperate that they’ll even kill for them. On October 31, 2009 that is precisely what the defendant Robert Nelson did,” Macomber told Judge John Nivisson.The victim, Everett Cameron, was diagnosed with non-Hodgkin lymphoma 7-years ago and prescribed, among other drugs, Oxycodone. Cameron started selling some of his prescription medication for extra cash. One of his customers was Robert Nelson.Prosecutors say Nelson owed Cameron $35 for pills and he refused to give him more until that debt was paid. “He wanted pills, but he didn’t have money for pills. So he fired a handgun at close range then took Mr. Cameron’s Oxycodone pills,” Macomber said.Police say after Nelson shot Cameron he went home to clean himself up then headed to his daughter’s 4th birthday party. “Robert Nelson was high on drugs when he arrived the party,” Macomber said. “His family members had never seen him in such a condition before. He was playing quite rough with his daughter.”Prosecutors also pointed out inconsistent statements Nelson made to police when he was first questioned about the murder. Police asked Nelson if they would find gunshot residue on his hands if they tested them. Nelson told police he had been target shooting with a friend the day before and probably would still have residue on his hands. Detectives interviewed the man Nelson said he was target shooting with. “At first he corroborated Mr. Nelson’s story about target shooting the day before the murder,” Macomber said. “Then on November 6, when detectives were driving him over to the pit in Solon so he could tell them where they had been shooting, the man admitted the story was a lie.” But the prosecution’s case is far from a slam dunk. Defense attorneys argue with no murder weapon, no DNA evidence, and no confession, the state is short on evidence. And given the fact the victim was selling his prescription medication Nelson wasn’t the only one with motive to kill him. “Mr. Cameron was a drug dealer,” said defense attorney Philip Mohler, “and frankly, there’s really no way to sugar coat that.”Mohler also argued the police focused in on Nelson early and never properly investigated others who could have committed the murder. “The simplest answer to why there’s no DNA evidence, to why there’s no gun tied to Mr. Nelson, the simplest reason why there’s no physical evidence tied to him other than his physical presence there at some point before Mr. Cameron was killed is the easiest answer. It’s because he didn’t do it,” said Mohler.Prosecutors admit there’s a long list of people who had motive to kill Everett Cameron, but only one person had the opportunity. “Your honor, when you apply common sense and reason to the evidence in this case, we’re confident that you will conclude that the state has proven beyond a reasonable doubt that it was Robert Nelson that killed Everett Cameron.”Nelson waived his right to a jury trial and now his fate belongs in the hands of Judge John Nivison. With more than 40 witnesses scheduled to testify, the trial is expected to last until early next week.If convicted Nelson will spend the next 25 years to life in prison.