When a Palo Alto police dog barked at Richard Dillon, the Menlo Park man barked back.

Dillon's actions didn't amuse Palo Alto police, who cited him on a misdemeanor charge of taunting a police dog. On Tuesday, Dillon pleaded not guilty in Santa Clara County court.

Now Dillon hopes to go to trial, because he thinks the charge is ``ridiculous,'' said his attorney, Donald Tasto.

Dillon was arrested March 5 at about 12:20 a.m., police said. He and a co-worker were walking down Ramona Avenue in Palo Alto after enjoying a night of Mardi Gras festivities, Tasto said.

As Dillon approached Palo Alto police officer Bob Wilkie's squad car -- occupied only by Odin, the canine -- Odin began to bark, said police spokesman Jim Coffman. As Dillon passed the open back window, he barked back at the dog. A heavy-duty wire screen was all that separated man and beast, Coffman said.

Police say Dillon not only barked, but also shook his fist at Odin. Wilkie cited Dillon on a charge of willfully and maliciously interfering with the duties of a police dog.

Dillon denies that he shook his fist at Odin, and said he only barked once at the dog, from a distance of about 10 feet, Tasto said. Neither Wilkie nor Dillon could be reached for comment Tuesday.

The charge, which carries a maximum penalty of a year in jail, is unfair for two reasons, Tasto said: Dillon didn't bark maliciously, and Odin wasn't working at the time.

Santa Clara County prosecutors said they couldn't yet comment on Dillon's claims.

``We are currently reviewing the law and investigating the facts in more detail,'' said supervising deputy district attorney Jay Boyarsky.

Dillon's next hearing in Santa Clara County court is Thursday.