PORTLAND — Seventeen-year-old convicted killer Christopher Fitch asked Friday for a new trial in the execution-style slaying of Norway hay farmer Lucien Frechette, but a judge rejected the youth’s motions.

Defense attorney Alan G. Stone promised an appeal to the Maine Supreme Judicial Court after Fitch is sentenced. Fitch faces 25 years to life in prison for the gunshot killing, which the state said occurred as Fitch and two other youths pulled off an armed robbery to get drug money from their 82-year-old victim.

The other youths, Jay Snow and Nathan Wade Conley, both 17, were acquitted in Penobscot County Superior Court. The boys from the Norway-South Paris area were all tried as adults.

Stone presented arguments on a series of post-trial motions Friday to Superior Court Justice Stephen L. Perkins, who presided over Fitch’s trial.

Fitch sat in the courtroom, his legs shackled. The teen showed no emotion and made no statements.

Stone said Fitch’s trial was unfair because of the wording of the judge’s final instruction to jurors and the exclusion of evidence that the defense contends pointed to an alternative suspect. After hearing from Stone and then getting the state’s arguments from Assistant Attorney General Thomas Goodwin, Perkins said he stood by all of the rulings he made at trial.

Stone said that the judge had watered down the meaning of the law when jurors interrupted their deliberations to ask some questions and the judge told them they could convict Fitch if they found his actions during the robbery “could” have led to Frechette’s murder.

By doing so, the judge allowed jurors to think they could convict Fitch based on the possibility that a murder could take place rather than the probability that a murder would take place, Stone said. Stone cited Webster’s Dictionary as well as rulings in other criminal cases.

The jurors apparently had been having trouble reaching a verdict, but once the judge used the word “could,” they came back rather quickly to announce they had convicted Fitch, Stone said. Goodwin said the judge’s instruction had been appropriate.

The defense attorney also complained that he was not allowed to bring in evidence indicating the crime could have been committed by another youth, Troy Landis, who was seen with a gun, drugs and cash after the robbery and murder of Frechette.

Goodwin then took the unusual step of asking the judge to let him present new evidence on Friday that Goodwin believed would have shot holes through the alternative suspect theory.

The judge sided with the state, telling Stone “the issue was speculative at best.”

Stone also said he was not allowed to introduce letters that would have further harmed the credibility of the state’s key witness, Shari Brown, who acknowledged on the stand she had lied during the murder investigation. The judge said the letters were not necessary.