Malik Cooper spent part of Friday transforming the facade of his silkscreen business on Webster Street into a mural bearing life-size images of Oscar Grant III.

On them, Grant is surrounded by scenes from the early morning shooting Jan. 1, 2009, and the violent protests that broke out downtown several days later: Helicopters hovering overhead, trash cans in flames, police officers in gas masks and cars set ablaze.

Cooper, the owner of People's Choice Silkscreen and Embroidery, put up about 100 of the posters and began handing out extras to other merchants.

"It's all the protection anyone is doing," Cooper said, referring to protection against the kind of violence that swept over several blocks downtown in January 2009.

"It shows support, that you're down with their cause," Cooper said.

He worried the city would force him to take down his stark black-and-red posters on the eve of closing arguments today in the Mehserle murder trial. Jury deliberations are expected to begin Friday.

The concern was that the posters would incite violence instead of protect against it. But tension around Oakland began to mount even before testimony in the trial concluded Tuesday.

A woman passing by Cooper's shop said she expected chaos. "I think they are going to acquit the cop. They always do."

With a verdict possibly days away, however, there is no way of telling what will happen — or when.

"We're getting ready, but also taking a stance," said Anita DeAsis, owner of the Oasis Restaurant and Bar on 12th Street. She picked up several posters from Cooper on Tuesday to hang in her windows. "We want people to know we are not part of the problem," she said.

Nearby city crews scrubbed off threatening graffiti around Lake Merritt even as stickers cropped up on garbage cans, bus stops and fire hydrants on 14th Street along the path taken in January by protesters. On one sticker is the image and Grant and the message "We don't forget." Another bears a picture of Mehserle and reads, "We don't forgive."

A flier stuck to a garbage can reads, "Day of Mehserle's Verdict 6 p.m.: City Hall. Be there." Yet another sticker is printed with "He says Tazer. We say Murder."

"There's no one listening," said Guy Karmi, whose wife owns the Spice Monkey restaurant near 17th and Franklin streets — a block hit hard by violent protesters in 2009.

He and Cooper worked late the night of the protests helping fellow merchants board up their windows. He said he wasn't sure if they would hang up a poster in the window this time. But merchants in neighboring shops already had. Those include Underground Treasures, a nearby boutique badly damaged during the 2009 unrest.

Meanwhile, the Bay Area Council called on police departments from the region's nine largest cities to provide aid to Oakland in the event of unrest after the verdict.

The Oakland Police Department already started ramping up this week for a worst-case scenario.

The owner of Purofirst, Rosa Rivera, said several people have called her about their service boarding up storefronts and repairs. But no one has hired them. That didn't keep some people from covering up storefronts on their own.

"Everybody's just waiting," Rivera said.

Oakland officials warned against "outside agitators" stoking tempers and listed places to "cool off and express yourself in positive ways" on the city website, www.oaklandnet.com.

"If a 'not guilty' verdict comes down in the Mehserle-Oscar Grant murder trial, we know many young people will feel a sense of outrage, anger and injustice. Let's not let these agitators make a bad situation worse," the message reads.

They recommended motorists park in secure locations and large trash receptacles be removed.

"It's a delicate situation," said Peter Van Kleef, owner of Café Van Kleef on Telegraph Avenue.

He had to shut the metal gate that covers the entrance to his bar during the 2009 protests. He decided then to hang a poster of Grant within sight of the street.

"I'm concerned for the city of Oakland. I'm hoping for the best," he said.

"The whole thing now is in the hands of the jury. Everything depends on that verdict."