Owen Labrie this week asked a New Hampshire court to throw out his conviction for sexually assaulting a 15-year-old fellow student at the elite St. Paul’s School, asserting that he deserves a new trial because his lawyers did not represent him effectively.

In a motion filed Tuesday, an attorney for Labrie claimed that counsel at his August trial did not sufficiently defend him against a felony charge that he used an Internet service to entice the underage girl.

Labrie was convicted on that count, along with misdemeanor sexual assault charges involving a minor. He was acquitted of separate felony allegations as jurors concluded that he had sex with the girl, but that prosecutors failed to prove he had acted without her consent.

The motion says Labrie’s lawyers at trial, J. W. Carney Jr. and Sam Zaganjori, carried out a “fundamentally flawed’’ strategy by not challenging the computer enticement allegation directly, either before or during trial.

That decision “resulted in a miscarriage of justice for Mr. Labrie,’’ his lawyer wrote.

Labrie was sentenced to a year in jail and was required to register as a sex offender for the rest of his life.

Labrie was convicted of assaulting the girl in a secluded room at the Concord campus in May 2014. Prosecutors said Labrie, who was 18 at the time, met up with the girl as part of a tradition called the “senior salute,’’ in which the school’s upperclassmen seek to have sexual encounters with younger students before graduation.

This week’s motion — filed by Jaye Rancourt, Labrie’s attorney on appeal — also contends that his lawyers should have challenged witnesses who corroborated allegations against Labrie by calling into question their own activities regarding the senior salute.

They also should have looked into the 15-year-old’s social media activity and used it to undermine her claims, the motion asserted.

“It was likely that [the girl’s] Facebook exchanges would have contained information which may have been used to challenge her credibility,’’ the motion read.

In a statement, Carney declined to discuss the motion in detail, but said that he agrees “completely’’ that the computer law “should not be applied to Owen Labrie given the evidence at trial and the jury’s verdict.’’

The law, and others like it, were “not meant to apply to teenagers who use Facebook to make plans to meet and have consensual sexual interactions,’’ he wrote. “It was designed to prosecute much older individuals who hide their true identities in order to induce minors to send them nude pictures or set up secret meetings.’’

Last month, Labrie was sent to jail for violating the terms of his release by missing court-ordered curfews.