Last night, protesters against police brutality took to the shopping complex at U-Village. For almost two hours, they walked silently in a line around the mall, singing in solemn tones, "Whose side are you on, friend, whose side on you on? Justice for Mike Brown is justice us for all."

No one was wearing a mask over their face. No one was shouting abuse at the police. No one was throwing rocks or firecrackers or anything else. "Are you sure this is a protest, not a church group?" asked one private mall security guard to her colleague, as she watched them go by.

But the police were out in force—there were more of them than protesters—to the surprise of the event organizers. Even before the demonstrators arrived at their meeting spot in the parking lot of a neighboring Safeway, the police were already there—at least ten police with batons and helmets standing in a group, a few feet away from where protesters huddled and talked in the cold.

Marissa Johnson and Nikkita Oliver, a UW law student, told me they'd organized the protest via text message and didn't advertise it on social media because they wanted to avoid the heavy police presence they'd experienced the previous night in downtown Seattle.

"How did all these cops get here before anybody else, positioned and ready?" asked Claire Sullivan, another UW law student who attended. "I don't have enough information to speculate."

Sullivan, Johnson, and a young woman who gave her name as Kalkidda told me that a middle-aged man with a beard had approached them from behind during the march. "I thought he was taking pictures of the bike cops, but then I realized he was taking photos of us," Sullivan said. When they asked the man for his name and badge number, having come to the conclusion that he was an undercover police officer, she said, he "straight-up bolted" across the parking lot.

I had a brief, similar experience with two men wearing puffy jackets and beanies in the parking lot, shortly before the singing march got underway. As I walked across the lot, a protester walking the opposite direction pointed to the two men and said, "Those guys are definitely informants." The men kept standing there in the middle of the parking lot, in the freezing cold, not particularly close to the entrance to any store.

I approached them, smiling and trying to suggest friendliness, and asked who they were and if they were police informants. One of them asked who I was. I identified myself as a reporter for The Stranger. The shorter man, with whitening hair peeking out from below his beanie, said sneeringly, "Well, I'm a reporter for the New York Times." I began pulling my business card from my pocket and offered to show it to them, but they waved me away. "We don't want to see your business card," the other man said.

I asked what their names were. "Joe," he said dismissively, not making eye contact. He lifted up his cell phone camera and took my photo. I reiterated that I was a reporter, that the protester had said they were undercover police, and asked who they were. He said he wouldn't talk to me. "Okay," I said. "Well, I'm just going to take your picture."

That set the men off. The shorter man immediately turned his back and walked away, briskly, across the parking lot. The other man, as I lifted up my phone, walked into me with his elbow jutting out, trying to prevent me from getting a clear shot and pushing me sideways. I asked the man what he was doing. "You're running into me!" he said. (The opposite was true.). Then he turned and followed the shorter man across the parking lot.

I followed, from a distance, and watched them enter the Eddie Bauer store and speak briefly with an employee, who led them through a door at the back of the store. I asked another employee who the men were. He said he would ask his manager. But after conferring with her over his earbud, he said the manager had wanted me to leave the store. I saw a female employee—perhaps the manager—peeking out at me from behind the door as I turned to leave.

If these men were undercover police, they were also three other things last night: unprofessional, awkward, and not very good at their jobs.

I asked Oliver, the UW law student and protest organizer, what impact the suspicions that undercover police are among them has on the protesters. "I think it causes people who want to exercise their rights to be on edge, and can automatically cause fear and distrust of the police," she said. "How do we keep people who come out in solidarity with us safe?"

In 2011, Brendan reported on seven Seattle police officers who went undercover, at a cost of hundreds of thousands of dollars, to attend a party held at a Capitol Hill apartment. "Oh wow, oh my god," said one of the party-goers, when he learned about the undercover officers. "That's terrifying. That's terrifying. That was such a nothing day, such a disorganized, nothing meeting."

Darrell Shelton, a black man, was on his way into the Microsoft store when the singing protesters passed by him. "I wish I'd known about this," he told one of them, taking a flyer. "You guys have touched my heart." He looked around at the police milling about at a Starbucks, and at the phalanx of bicycle cops trailing the marchers. "I think it's a waste of resources," he said. "The cops are really a deterrent for people speaking their mind. That's what it is. That's a sad thing."

I recounted all of this last night to Seattle police spokesperson Sean Whitcomb. His response was confusing—and Whitcomb is generally very good at his job, at times speaking about the police with a refreshing degree of candor. First, he said, he wanted to check with his colleagues about whether there were undercover police present.

"Cover blown is a big deal," he said, as he hung up.

When we next spoke, he said he'd checked in with Assistant Chief Paul McDonagh. "How best to say this," he said. He paused. "I'm not going to be able to confirm that those were our people. I'm certainly not going to deny it."

Whitcomb stressed that it was normal for SPD to deploy police in plainclothes at "special events" like New Year's or Fourth of July. He said the Ferguson protests fit into that same category, in light of the broken windows and items thrown by some protesters at police last week. "It helps us see things that we might not otherwise be able to see," he said.

He said confirming that those men were police would put them at risk—even though we were talking long after the protest had ended, and I told him I wasn't going to publicize their names or faces, neither of which I had on record.

"We don't do undercover," he said. By undercover, he said he meant, "I've adopted a different persona. I've basically represented my identity differently to people in order to gain their trust, so I can elicit information to move forward a criminal investigation."

But later, he seemed to contradict himself: "If there was an undercover, I wouldn't even know about it."