A state court ⁠judge in New Mexico has dismissed charges of child sexual abuse against West Wing actor and director Timothy Busfield, saying the prosecution did not act in a ⁠fair and impartial manner during grand jury proceedings.

Judge Joseph Montano said prosecutors could pursue new charges against Busfield.

The actor has strongly denied allegations ⁠of improperly touching two young boys – twin brothers – on the Albuquerque set of Fox TV ​drama The Cleaning Lady.

A spokesperson for ‌the second judicial district ‌attorney office of New Mexico said the office was evaluating its options.

The twins reported that ‌the alleged contact had occurred over a two-year period, when they were aged seven and eight, during breaks in production, prosecutors said in a criminal complaint filed in January.

Busfield, a director and producer of The Cleaning Lady, was charged in February in a four-count grand jury indictment that accused the actor of groping one of the ‌boys.

He steadfastly professed his innocence, calling the allegations against him “lies”, and his attorneys asked for the charges against him to be dismissed.

In Friday’s ​ruling, Montano said the prosecution did not properly instruct members of the grand jury on procedures for requesting testimony from additional witnesses. In part, the prosecutor incorrectly informed the grand jurors that at least eight of them would have to agree to wanting to hear ⁠from a witness for that person to be called.

“The prosecuting attorney failed ​to act in a ​fair and impartial manner,” Montano wrote, ​adding that the lawyer’s actions “had the practical effect of unilaterally withholding witnesses ​requested by the ‌grand jurors”.

Busfield, 69, ​is best known ​for his prime-time television roles as a White House reporter on the NBC political drama The West Wing and as an advertising agency executive on ABC ensemble series Thirtysomething. He also appeared in the baseball film Field of Dreams” starring Kevin Costner.