Sentry challenges come with occupation

Sergeant John McBrien, a 23-year-veteran with the department, barely gave them a passing glance. “Those are the anarchists,’’ he said casually, then turned his gaze back to the makeshift camp of Occupy Boston.

Three weeks after the tent city sprouted near South Station, a takeover that at one point led to mass arrests and tense confrontations with police, officers and protesters have settled into a calm routine.

Four to five officers stand sentry 24 hours a day in Dewey Square, where demonstrators organize marches, hoist protest signs, and practice yoga in relative peace. Police, demonstrators say, are giving them plenty of space and, in return, ask only for updates on any planned marches so they can coordinate traffic. Occasionally, officers and protesters engage in small talk, chatting about sports and the weather.

“I think we’re enjoying a much better relationship,’’ said demonstrator Liam Leahy, a 33-year-old North End man, as he smoked a pipe in a tent deep inside the camp. “I think we’re at a much better place right now.’’

Officers, McBrien said, are following their marching orders: Patrol outside the camp; go inside only if a crime is committed.

“If they have a problem, they can come to us,’’ he said. “We stay out here in the perimeter.’’

It can get a little boring, McBrien acknowledged.

“A lot of standing around,’’ he sighed as he stood near the camp on Thursday, bracing himself against a strong wind that threatened to blow away the dozens of tents set up between Congress and Summer streets.

It was McBrien’s third time monitoring the demonstration, which is a protest against economic inequality, a movement that has spread to dozens of other cities and countries and has sometimes resulted in ugly standoffs with police that have been recorded and disseminated on the Internet. In New York, where hundreds of protesters have been arrested, a high-ranking officer was suspended after dousing several female demonstrators with pepper spray.

Last week, Boston police arrested 141 people when they moved to a swath of the Rose Fitzgerald Kennedy Greenway and refused to leave. The arrests drew outrage from the protesters, who have announced plans to demonstrate outside the department’s Roxbury headquarters today.

But at camp, relations between the officers and demonstrators are at worst neutral, said one protester.

Officers watch demonstrators, sometimes bemused, sometimes admiring the organization of the camp, where separate tents have been set up for food distribution, donation collections, and scheduled activities.

“Soon, they’ll be getting mail,’’ quipped Officer Alex Reyes, an East Boston patrolman who has worked four shifts at the camp. “I’m slightly entertained. It’s their own little society, the way they’ve been able to sustain themselves.’’

Still, life at Occupy Boston has not been totally tranquil, according to police, who have spent about $150,000 in overtime to cover shifts at the square.

On Tuesday, officers reported they broke up a drug deal at the camp. Two days later, a member of Occupy Boston reported his laptop was stolen. On Sunday, several members of the movement told police that a man, who had come into the camp and urinated on a tent, pulled a knife on them after they asked him to leave.

Police said they have heard other reports of robberies at the camp, but victims have not come forward, leading officials to worry that demonstrators are reluctant to cooperate with them.

A security team, which includes two homeless men who don neon green-yellow jackets and patrol the camp, has been set up to monitor for trouble, said Jason Potteiger, a camp spokesman.

“We’re very good at policing ourselves,’’ he said. “We have a see something, say something policy.’’

Still, demonstrators want the police to interfere when crimes are committed inside the camp, Potteiger said. Officers have been asked at least once to come and remove unruly people causing trouble, including one man who recently stripped naked and began to walk around the camp.

“The relationship we have with the police is very different than what it is in New York City,’’ Potteiger said. “Even after the arrests, people would be very comfortable approaching them with any problems.’’

Leahy said that patrol officers have approached him and told him they support the cause.

“They say, ‘I understand what you guys are doing here,’ ’’ Leahy said.

One demonstrator, a 25-year-old piano technician who identified himself as Rene, said that he gave some officers pins bearing slogans of the movement.

“They seemed very grateful,’’ he said.

Commissioner Edward F. Davis declined to say how police would handle demonstrators if and when city officials decide they must leave the square, even if force is required to move them.

“We’ll cross that bridge when we come to it,’’ he said. “We’re in a situation where we’re protecting First Amendment rights, but also the safety of the city, so it’s a balancing act.’’

Asked whether police hope that the hard New England winter could do the work of clearing the square, Davis replied, “I wouldn’t complain about that.’’

Maria Cramer can be reached at mcramer@globe.com. Follow her on Twitter @GlobeMCramer.