Updated

Prosecutors have withdrawn a subpoena for a man ordered to testify about a violent late-November clash between police and Dakota Access pipeline protesters in which a woman suffered a serious arm injury.

But it's unclear whether a grand jury is still looking into the confrontation in which protesters unsuccessfully tried to push past a blocked bridge on a state highway near their main encampment in North Dakota.

U.S. Attorney Chris Myers has said he can't comment because grand jury proceedings are secret.

Forty-two-year-old Steve Martinez was ordered to testify in January. At the time, he said he would refuse to cooperate and was willing to go to jail.

His attorney, Ralph Hurvitz, says the subpoena was withdrawn Monday, two days before Martinez was to testify. No reason was given.