Philadelphia Safe and Sound, a social-service charity with connections to former Mayor John F. Street and his wife, is under investigation by the FBI, according to several people familiar with the issue, reports The Philadelphia Inquirer.

The charity split up in June after Philadelphia’s current mayor, Michael Nutter, expressed concern about its expenditures and programs. Sources said federal investigators were looking into whether the group had improperly distributed tens of millions of city dollars it had received throughout the Street administration intended to oversee after-school programs, antitruancy efforts, and curfew centers and to conduct violence-prevention research, the newspaper said.

Mr. Street’s wife, Naomi, was director of the nonprofit organization from its founding in 1998 until 2002. According to sources, the federal inquiry appears to be centered on the work of specific providers, including Lucinda Post, Ms. Street’s sister, who for at least the past five years managed Safe and Sound-supported programs that received millions of dollars.

Neither Mr. Street nor his wife responded to the newspaper’s calls for comment. Ms. Post denied any wrongdoing.