The last thing San Francisco needs is more friction between bicyclists and the police, but events this week only increased the tension.

It happened at Sixth and Folsom, site of a tragic bike-truck accident on Aug. 14 that took the life of 24-year-old Amelie Le Moullac. Le Moullac, who worked at a communications firm nearby, was killed when a large truck struck her while making a right turn.

A week later, during the morning commute, members of the Bicycle Coalition and four of her co-workers set up a memorial and information table on the corner.

It was a typical event for the coalition, which advocates for better bike lanes and safety awareness. The moderate group, media savvy and politically aware, should not be confused with the radical bike groups like Critical Mass. Executive Director Leah Shahum says she even called San Francisco police and the Municipal Transportation Agency ahead of time to let them know about the gathering.

All went well until Sgt. Richard Ernst rolled up in his police cruiser and parked in the street, blocking the bike lane.

"He said he was, quote, setting an example," Shahum said. "He said, 'I am here to prove a point that bicycles need to go around the car. This is the exact situation as the one where the woman was killed.' "

Ernst's argument, apparently, was that bicyclists often stay to the right side as a vehicle turns, putting them in a truck's blind spot when it turns. Ernst's comments were recorded by the media, including KRON-TV, which captured him saying, "I was trying to show her, as an example, where cars are going to be."

In all, there have been three fatal accidents in or near the South of Market area in the past year, each the result of a collision with a large truck.

"The officer said, 'In all three of those cases, it was the bicyclist's fault,' " Shahum said. "I said I had been talking to officers and my understanding was that they were still investigating this one. He said, 'I've read the report. You haven't read the report. It was her fault.' "

The ham-handed approach was ill-advised enough. But what Ernst didn't know was that four of Le Moullac's co-workers (who are not members of the coalition) were standing on the corner, listening to him lecture Shahum about bike etiquette.

"He said, and I quote, he would not leave until I understood that it was the bicyclist's fault," Shahum said. "The friends and co-workers of the victim were within earshot and they were very agitated."

SFPD brass did not comment directly on Ernst's actions, but privately they confirmed that not only was he acting on his own, they considered his actions an embarrassment.

Later, when Shahum called to complain, she was directed to Southern Station Capt. Michael Redmond, who returned her call immediately and walked her through the process of filing a complaint.

But as unfortunate as all that was, there was an even more disturbing development after the morning memorial.

Shahum said a member of her group, noticing a video camera on one of the businesses, suggested stopping in to see if it captured the accident.

Previously, Shahum said, police told her they'd checked stores with cameras but hadn't found anything usable. But when they stopped in, Shahum said they were told police officers had never asked to see their tapes.

Apparently one of the cameras had a view of the accident.

"We were told that the footage gets taped over every seven days," Shahum said. "And this was exactly a week after the accident. So by the next day it would have been gone."

Shahum hasn't seen the footage, but it was turned over to the attorney for Le Moullac's family, who says the video is "helpful."

This certainly won't be the last we'll hear of this.