The National Fair Housing Alliance on Wednesday expanded its complaint against Bank of America over neglecting the maintenance and marketing of foreclosed homes in black and Latino neighborhoods.

The complaint, filed with the Department of Housing and Urban Development a year ago, offers additional evidence and includes five new cities — Denver, Memphis, Las Vegas, Tucson and Philadelphia. All told, the advocacy group said it has unearthed discriminatory practices in the way Bank of America handled 621 properties in 18 metropolitan areas.

The allegations arose out of a year-long investigation by the alliance, which found that homes serviced by Bank of America in minority communities were far more likely than those in white areas to be left in disrepair, with broken windows, unkept yards or water damage. These homes were also less likely to have for-sale signs than ones in predominantly white neighborhoods.

“Every day, Bank of America continues to neglect homes it owns in communities of color and prices decline, allowing investors to snatch up these foreclosures, turning communities into neighborhoods of absentee landlords,” said Shanna Smith, president and chief executive of the D.C.-based alliance, a coalition of more than 220 nonprofit and consumer groups.

Officials at the bank argue that the alliance’s report was riddled with inaccuracies and its methodology was flawed.

Company spokeswoman Jumana Bauwens said some of the properties that the alliance found fault with in the original complaint were the responsibility of other parties, including the Federal Housing Administration. She said the alliance also did not take into account the condition of the homes when the bank received them.

“We are fixing up these houses, but can’t do it on their time scale. We have to do it when we have full ownership and legal right to enter the property,” Bauwens said, noting that Bank of America is negotiating with HUD.

Smith took issue with the bank’s characterization of the study, stressing that the alliance did not evaluate homes that had been transferred out of the bank’s possession or were occupied. She pointed out that in every neighborhood the alliance studied it looked at all of Bank of America’s properties for comparison.

In one instance, alliance members visited a foreclosed home in Capitol Heights and one in the District that were dilapidated, with trash on the lawn, gutters missing and overgrown lawns. But in a predominantly white neighborhood in Rockville, the advocacy group said bank-owned properties were in top condition.

“This discriminatory treatment discourages purchasers from buying homes in minority communities,” said Janell Byrd, a housing lawyer. “It reinforces the difference in property values between majority-white and majority-minority communities. And it exacerbates a gross disparity between the wealth of whites and minorities.

The charges highlight one of the lingering scars of the housing crisis. As the number of foreclosures climbed in the aftermath of the housing crash, lenders scrambled to offload foreclosed properties, with many piling up in minority neighborhoods where there was a high concentration of subprime loans.

These high-priced mortgages with onerous terms were offered primarily to minorities.Communities have been eager to see these vacant properties sold because over time they can bring down property values and attract crime, consumer groups say.

The alliance has filed two similar complaints against U.S. Bank and Wells Fargo. Negotiations with U.S. Bank have reached an impasse, according to the consumer group. Earlier this year, Wells Fargo settled the complaint by providing $42 million to nonprofit groups to promote homeownership, neighborhood stabilization and property rehabilitation in minority communities in 19 metropolitan areas.