HOULTON – A man who is on trial on charges of murdering three people told investigators that one of them was a drug dealer who caused pain in his life and the others were “perfectly innocent,” according to a videotaped interview that was shown to jurors Thursday.

The videotape captured Thayne Ormsby telling investigators that he had never met Jeffrey Ryan but knew of him through mutual friends. Ormsby said he hoped to rid the world of a “bad person” by killing Ryan.

Also killed on June 22, 2010, at Ryan’s home in the Aroostook County town of Amity were Ryan’s 10-year-old son, Jesse, and a family friend, Jason Dehahn, 30.

Ormsby, 22, who’s charged with three counts of murder and arson for setting fire to Ryan’s pickup truck, is using an insanity defense.

He told police during the interview that he didn’t plan to kill Dehahn or the boy. “I didn’t want to kill them, but I didn’t want to get caught for murder,” he said.

The testimony came after the defense made a motion for a mistrial, saying the jury was “tainted.”

On Tuesday, a relative of one victim told a juror to “hang” Orsmby, but the juror was allowed to remain. On Wednesday, an alternate juror was dismissed after trying to shake the prosecutor’s hand and telling him he was doing a “good job.”

Ormsby’s attorney, Sarah LaClaire, said those cases underscore her contention that Ormsby can’t get a fair trial in Aroostook County. The judge questioned all jurors Thursday before denying the motion for a mistrial and allowing the videotape to be shown to the jury.

On the videotape, Ormsby described in graphic detail how he fatally stabbed Ryan, 55, before going into the home to stab Dehahn and following the boy into a bedroom to kill him. Afterward, Ormsby said, he chased down the injured Dehahn and killed him outside near a ditch.

When police asked him what they should do next, Ormsby replied: “You need to arrest me first, for starters.”

The trial in Aroostook County Superior Court is expected to continue through next week.