A convicted killer is on trial Monday in Rockland, charged in connection with another death.The trial of the State of Maine versus Maine State Prison inmate, 50-year-old Franklin Higgins, for two counts of aggravated attempted murder, got under way at Knox County Superior Court.”What is a substantial step? Just preparing to commit a crime isn’t enough. A substantial step is any conduct beyond mere preparation and is strongly cooberative and a firmness of an active intent to complete a crime,” said Assistant Attorney General Leane Zainea.The crime the prosecution is talking about is an assault involving Maine State Prison inmate, Franklin Higgins.The assault happened in the prison woodshop, where Lloyd Millett, also convicted for murder, was injured.Millett died two weeks later of heart disease. The prosecution claims the injures sustained during the assault led to Millett’s death.”Now, as you’re sitting here, you’re probably asking yourself why. Why would Frank Higgins do this? Why would he attack Lloyd Millett? Well, days before the attack, Lloyd Millett confronted and hit Franklin Higgins. And, that can’t happen in the prison without retribution and revenge,” said Zainea.But the defense said Millett threatened violence to extort money from Higgins.”As he’s waking there, Lloyd Millett sees him and turns on him. And, when Lloyd Millett turns on him, Frank Higgins, in that split second, does the only thing he can think of. He hits with the pipe. He hits him twice, and Lloyd Millett goes down, and Frank Higgins drops the pipe clamp, and walks back. This is a case of self defense,” said defense attorney Phillip Cohen.During opening statements, the prosecution said video from the workshop shows Higgins walk the into an area where Millett was found with a pipe-clamp, and he later walked out with out the pipe-clamp, and that Higgins intended to assault Millett.But, the defense says Higgins was using the pipe-clamp for a project he was working on that day.”He has to glue two pieces together. You use a pipe-clamp to do that,” said Cohen.The state called multiple witnesses to the stand, including inmate Tracy Medicine, who was working in the shop the day of the assault.He said he was one of the first to find Millett, who was bleeding on the floor by his machine, which was still running.Due to a snow storm expected to hit on Tuesday, the trial has been postponed until Wednesday.