CHICAGO (CBS) – Some of the harshest words yet in the race for mayor came on Monday.

Frontrunner Rahm Emanuel toured a factory, taking credit for keeping the employer – Chicago Paper Tube & Can Company, and its jobs – in Chicago.

READ MORE: Protesters Say Benet Academy In Lisle Rescinded Lacrosse Coach's Job Offer Because She Is A Lesbian

“I knew the developer. Knew him, called him, and said you’ve gotta help make this happen,” Emanuel said. “And making sure the bottom line worked for everybody.”

Meanwhile, challenger Miguel Del Valle tore into Emanuel for torpedoing immigration reform in Congress.

READ MORE: Metallica Performs Surprise Show At The Metro

“We don’t have immigration reform in this country because a number of legislators have not had the courage to act,” said Del Valle. “Rahm Emanuel had the opportunity to act and he didn’t have the courage to act. Quite the opposite: he advised his colleagues not to act.”

The Emanuel campaign says Del Valle is wrong, and that Emanuel worked to improve life for immigrants.

But the fact remains that Latino lawmakers blame Emanuel for the absence of immigration reform in Washington.

MORE NEWS: Chicago Weather: Cold Front On The Way

CBS 2 Political Producer Ed Marshall contributed to this report.