CHICAGO — A group headed by a former Chicago alderman has submitted a bid to purchase the Chicago Sun-Times.

The investor group led by former Alderman Edwin Eisendrath and the Chicago Federation of Labor, an umbrella group of labor unions, submitted a bid Monday by a 5 p.m. deadline.

Terms of the offer to buy the Sun-Times and Reader from Wrapports LLC were not disclosed. Eisendrath said the effort has raised about $15 million, supported by 10 to 15 unnamed investors.

Eisendrath said the paper would adhere to its tradition as a voice for the working class.

Chicago-based Tronc, which owns the Chicago Tribune, the Los Angeles Times and other major newspapers, announced May 15 it had entered into a nonbinding letter of intent to acquire Wrapports.

The U.S. Justice Department asked Wrapports to extend a deadline to allow bids from other potential buyers.