A man accused of smashing the windshield of a San Francisco Municipal Railway bus last week after the Giants' World Series victory pleaded not guilty to two felony charges Monday but his attorney said he acknowledges responsibility for the incident.

Gregory Graniss, 22, pleaded not guilty to felony vandalism and willful tampering with a passenger transit vehicle -- the 8X-Bayshore Express bus that he allegedly targeted at Market and Third streets during the revelry early on Oct. 29 after the Giants had clinched the World Series.

Graniss, who came to court with his parents, spoke only briefly during the arraignment that afternoon. However, his attorney Douglas Rappaport said outside of court that his client acknowledges his role in the vandalism and is asking for forgiveness from San Franciscans.

"The Giants' victory was amazing and it really brought out the best in San Francisco and unfortunately the worst in Gregory," Rappaport said. "He is very ashamed of his actions and very, very sorry."

A San Francisco Chronicle photographer captured a picture of a man smashing the windshield of the bus with a metal police barricade during the raucous celebration.

The image was circulated widely, and social media users helped identify Graniss as the suspect. He turned himself in to police on Tuesday.

Graniss is out of custody on $40,000 bail and would return to court on Dec. 17 for a pre-hearing conference.

District Attorney George Gascon held a news conference after the arraignment and said he hopes Graniss' arrest will not be the only one in connection with the bus vandalism.

At least one other person was photographed smashing the windows of the bus, while a video recorded by a bystander showed two suspects lighting the vehicle on fire. That video was released by police last week and was made available on KTVU.com

The bus, which cost $700,000 and recently had about $300,000 in rehabilitative work done to it, was destroyed in the fire. Eight passengers and the bus driver got off the bus safely before it was set ablaze.

"This is a time for the city to celebrate, but unfortunately there were a few people who decided that they were going to damage property and injure others," Gascon said.

While the other arson and vandalism suspects in the Muni bus case have not yet been arrested, prosecutors have charged a total of 12 people for other post-World Series incidents, including assaults on police officers, robbery, vandalism and discharging a firearm from a window, Gascon said.

About 20 others were arrested and cited for various misdemeanors or for public intoxication, police said.

The district attorney said his office may seek restitution from Graniss for damage to the bus. City Attorney Dennis Herrera has also said he plans to pursue restitution from anyone found to have damaged city property.