AUBURN — A former Bates College student is expected to call a martial arts expert to the stand at his upcoming trial in an effort to beat an assault charge by attempting to show that a Lewiston police officer broke his own leg using poor technique while trying to throw the defendant to the ground.

At a pretrial hearing Thursday in Androscoggin County Superior Court, Bob Morissette demonstrated for the judge the method Sgt. Robert Ullrich used when grappling with Samuel Guilford during a melee at the Bates College campus in May 2010.

Roughly 300 students converged on Smith Hall the night of May 26 last year. College security officers were overwhelmed by the crowd and called in the Lewiston Police Department, whose officers eventually broke up the group. Campus security complained the students were blocking an ambulance called to Smith Hall.

Police arrested and charged 11 students in the incident, most with failure to disperse.

Guilford was charged with aggravated assault, refusing to submit to arrest, disorderly conduct and failure to disperse.

Guilford and three others waived their rights to a jury trial and are scheduled for a bench trial on Nov. 1. The cases against the remaining seven students who were charged have been resolved. Guilford graduated last year.

On Thursday, Guilford’s attorney, Leonard Sharon, offered Morissette as an expert who is expected to testify that Ullrich’s poor technique in trying to subdue Guilford caused the police officer’s broken leg. Morissette said he viewed a video of the incident and concluded that Ullrich, who had wrapped his arms around Guilford’s waist from behind, should have thrown him to the left, following the direction in which Guilford was moving. Instead, Ullrich resisted Guilford’s momentum and threw him to the right, while Ullrich tried to pivot on his right heel, Morissette said.

Before he was told what happened as he viewed the videotape, Morissette predicted Ullrich would injure his right leg, Morissette said under oath in the Androscoggin County Law Library, which was used as a makeshift courtroom.

Morissette, 36, of Lewiston said he has been studying martial arts for 26 years. He has studied and taught several styles of martial arts, including judo, and attained the rank of third-degree black belt in one of them. He has taught police officers proper throwing technique, he said.

He said he couldn’t identify the throwing technique used by Ullrich during the incident and said the officer was moving the wrong way and wasn’t on the proper part of his feet for a successful take-down.

Under cross-examination by Assistant District Attorney Andrew Matulis, Morissette said he lacked formal training in the sciences of physics and medicine and didn’t know what injury reconstruction was. He also said he hadn’t analyzed videos before to draw conclusions about resulting injuries.

Justice MaryGay Kennedy said she would allow Morissette to testify at Guilford’s trial as a “highly qualified” martial arts instructor, but questioned the scope of his expertise in his ability to draw conclusions about Ullrich’s injury, noting that Morissette’s experience is limited to controlled environments.