ALBURGH, Vt. -- A Vermont man has pleaded guilty to charges that he sprayed liquid cow manure on a U.S. Customs and Border Protection car after confronting an agent about why he wasn't doing more to arrest people in the country illegally.

MyChamplainValley.com reports that Mark Johnson, of Alburgh, entered pleas Tuesday to simple assault on a law enforcement officer with bodily fluids and disorderly conduct.

Johnson, who does custom manure spreading, was charged in August after his manure spreader covered a cruiser parked about 2 miles (3 kilometres) south of the Canadian border.

Johnson initially said he didn't know the agent was behind him. He later said he asked the agent why more wasn't being done to arrest immigrants in the country illegally.

A plea deal requires Johnson to do 24 hours of community service and write an apology letter.