CHICAGO -- The Dave Matthews Band pleaded for patience from its fans and the people of Chicago as police continued to investigate allegations that a bus the band used dumped human waste onto a tour boat in the Chicago River earlier this month.

"We are not attempting to avoid any responsibility," a statement on the band's Web site posted Sunday read. "If we were responsible for what happened, we will work quickly to make amends."

The band was cooperating fully with authorities, the statement said, and the band offered photographic evidence, license plate numbers, access to its drivers and tour manager, as well as DNA samples from band members.

The band emphasized its love for Chicago and its people, but also a sense of loyalty to a driver who has worked with the band for five years, according to the release.

"In that time he has earned our respect and trust and on a personal level he has become part of the family," the statement said.

The band also stated that it had yet to see all the evidence, and had a "few narrow but critical questions related to what we have seen of the evidence in the media."

Police were conferring with the Illinois Attorney General's office, the Cook County State's attorney's office and the U.S. Attorney's office to determine if criminal charges would be appropriate, Belmont Area Cmdr. Michael Chasen said at a Wednesday news conference.

Charges had not been filed as of 8 a.m. Monday, police News Affairs Dep. Director Pat Camden said, though police were still investigating.

Police showed a security video Wednesday of a bus they said was used by the Dave Matthews Band, and was the source of the human waste dumped on Aug. 8 on a Chicago Architecture Foundation tour boat as it passed beneath the Kinzie Street Bridge.

The footage showed a tour bus with a white base crossing the bridge less than two minutes before a police report stated the waste rained down on the boat passengers, Chasen said.

The video clocked the bus passing at 1:18 p.m. and 18 seconds, while the police report stated the boat passengers were struck with the waste at about 1:20 p.m., Chasen said.

No other buses crossed the bridge on the video for 15 minutes before or after, he added.

One of the boat passengers, who had noted seeing a long black tour bus passing overhead when the waste poured down, later saw a similar bus in the downtown area, and gave its license plate number to the architecture foundation, which in turn notified police, Chasen said.

Police traced the plate to the Four Seasons Coach Leasing company in Lebanon, Tenn., and learned that the company had leased 10 buses to the Dave Matthews Band, Chasen said.

Police did not know the license plate number of the bus captured in the video, Chasen said.

The Illinois Attorney General's office filed a civil lawsuit against the band on Tuesday, accusing them of dumping the waste.

The suit claimed that either the band or its bus driver, Stefan A. Wohl, dumped between 80 and 100 gallons of the "foul-smelling, offensive" waste from the bus down through an open grating in the bridge.

That waste splashed onto the approximately 109 tour boat passengers, including disabled people, senior citizens, a pregnant woman, a small child and an infant, the suit stated.

The suit charges both the band and Wohl with violating state water pollution laws, as well as common law public nuisance laws. It seeks a penalty of $60,000 for the water pollution violation and $10,000 for a permit violation, according to the Illinois Attorney General's office.

The case was assigned to Presiding Chancery Judge Dorothy Kinnaird for a case management hearing in January.