BISMARCK, N.D. - A judge in North Dakota has dismissed the remaining charge against a South Dakota man who prosecutors alleged was part of the 2016 riot at the Dakota Access pipeline construction site.

The prosecutor and defence attorney requested that the misdemeanour charge of engaging in a riot be dropped against Lawrence Malcolm Jr. , of Sisseton, South Dakota. South Central District Judge Bruce Romanick signed the order Tuesday, The Bismarck Tribune reported.

Defence attorney Bruce Nestor filed a motion to dismiss, saying prosecutors waited too long to file the charge. The statute of limitations for the offence is two years. The criminal complaint was filed almost three years after the alleged offence, Nestor said.

Assistant Morton County State’s Attorney Chase Lingle filed a motion Tuesday to dismiss, saying “the Court has made statements that concern the State about its ability to prove” the charge at trial.

Lingle did not respond to requests seeking comment on the case.

Earlier this month the judge dismissed a felony criminal mischief conspiracy charge against Malcolm for lack of probable cause. Malcolm was charged based on DNA from a cigarette butt left at the scene. His DNA was on file from a previous arrest.

Nestor countered that it was impossible to determine where the cigarette butt originated or how long it might have been there.

An affidavit says more than 100 demonstrators halted construction and vandalized equipment during the protest on the Standing Rock Indian Reservation.