PORTLAND, Maine — A local transient with ties to Aroostook County accused of spitting in the face of a postal clerk last year has pleaded guilty to assault on a federal employee.

Derek P. Dow, 27, pleaded guilty Monday after U.S. District Judge Nancy Torresen found him competent to enter a plea to the charge. He was released Thursday on $5,000 unsecured bond with the condition that he live with his mother in Presque Isle, according to court documents.

Dow had been held without bail since his arrest Dec. 20 in connection the incident at the post office on Forest Avenue in Portland 10 days earlier. In February, Torresen ordered that Dow undergo a psychiatric evaluation and treatment at government expense.

By pleading guilty, Dow admitted to spitting on a postal clerk, “hitting him on his right ear, the base of his neck and the left side of his face,” according to the prosecution version of events to which he pleaded guilty. Dow became angry on Saturday, Dec. 10, when the clerk told him that he could not pick up his mail until the next Monday, Dec. 12. Dow’s mail had been put on hold until Sunday, Dec. 11, according to the complaint. The incident was captured on video.

During a Dec. 12 interview with a postal inspector, the defendant admitted spitting in the clerk’s face, according to the complaint. Dow said that “the government, the Portland police department and the post office were all part of a conspiracy against him and the Micmac Tribe of Native Americans,” the complaint said.

Dow faces up to a year in prison and a fine of up to $100,000.

His sentencing is scheduled for Oct. 22 in federal court in Portland.