When Pearce entered Miramar yard facility, a man came from a parked van and mooned him. Pearce snapped away while the city uniform was draped around his ankles.

When San Diego city employee Marcus Arenas pulled down his pants and mooned Harold Pearce, Pearce knew something was up. Pearce had been photographing Arenas and other city workers as they hoisted a beer keg up a flagpole during a raucous party at a Scripps Ranch water-treatment plant. The festivities were in honor of a co-worker who had just been named the water department’s “employee of the quarter." But for many at the affair, it was their last good time on the public payroll. Three of them were fired and arrested after Pearce claimed they beat him up and stole his camera for taking pictures of the mooning and municipal mirth-making.

The August 3 party started when the afternoon shift ended. More than a dozen workers were enjoying music and booze. (This is usually not allowed on city property unless a member of the city council is present.) Within two hours, neighbors heard laughter, yelling, and screaming for blocks around. But it was the beer barrel floating high above Scripps Lake Boulevard that got Pearce’s attention. “They were really raising hell,” Pearce said. “There were two of them down at the flagpole raising the keg, and the rest of them were standing up there cheering."

Pearce grabbed a camera and took pictures of the keg and the party, first from his front yard across the street and later from inside city property. “So I’m taking these pictures and they see me. So they yell, ‘Hey, take my picture,’ and they were toasting each other. So I started thinking, wait a minute, there’s something seriously wrong here.”

That’s what Daryl Grigsby, deputy director of water utilities, found after a two-month investigation. Grigsby sent termination notices to all the partygoers for conduct “offensive to the public.” He wrote: “By 5 p.m., only nine employees remained....

At the time that Mr. Pearce entered Miramar yard facility, he noted that an Hispanic-looking man [later identified as Marcus Arenas] came from a parked van, said to take a picture of him, and then he mooned him by taking down his pants, turning around and then bending over.”

Pearce snapped away while Arenas’s city uniform was draped around his ankles. Pearce said: “Then the guys in the party see what this guy was doing, and they said, ‘No, no, no, no, no.’ Then they saw me taking pictures of him that camera.’ ”

Then it got ugly. Arenas and two other public employees allegedly grabbed Pearce, pushed him around, stole the camera, and exposed the film. “Then they said I was trespassing on city property and I should get the hell out.... So as I’m bending down to pick up my cigarette lighter, this little short idiot [Arenas], he came up and tried to stomp my hand.”

Grigsby’s report picks up the story. “Most if not all of the employees were around him at this time, and he felt physically threatened. He had to leave the area because he felt attempts to retrieve the camera would result in physical harm.”

Pearce called police, but the party was over when they arrived. He refused medical attention after the incident but later saw a doctor for heart pains he said were caused by the scuffle. The 59-year-old Pearce eventually identified three city employees, all in their late 20s, as his attackers; and Arenas, Adam Lorta, and Ronald Evans (the “employee of the quarter") were charged with misdemeanor theft and assault. Charges against Evans were later dropped after the city attorney determined he was not involved.

Lorta did not show up for a January hearing, and a warrant has been issued for his arrest, court records show. He could not be reached for comment. Arenas is awaiting trial and did not return phone calls. Officials at the city water department refused to comment on the incident or any action they took against the men. But sources said that with the exception of Lorta, Arenas, and a third, still-unidentified man, the city later rescinded its decision to terminate all the revelers. Evans and others, however, were suspended for five days for initially refusing to cooperate with Grigsby’s investigation, said David Siegel, Evans’s attorney.

Meanwhile, Pearce filed a $35,000 claim against the city in February for “serious emotional and physical injuries." The city has not responded to Pearce’s complaint, but a week after the festivities, water department workers posted several large signs, many visible from Pearce’s home, which warned: No Trespassing.