Senator Amy Klobuchar, Democrat of Minnesota, has been asked by Joe Biden to undergo a formal vetting to be considered as his vice presidential running mate, one of several potential contenders now being scrutinized by his aides ahead of a final decision, according to people familiar with the moves.

The request for information from potential running mates like Klobuchar “is underway,” a senior Biden campaign aide tells CBS News.

And Senator Richard J. Durbin, Democrat of Illinois, told reporters last week that his Land of Lincoln colleague, Senator Tammy Duckworth, is also set to be interviewed by the Biden team – a statement Duckworth aides also disputed.

Several prominent African-American leaders close to Biden are pushing for Demings, Senator Kamala Harris, Democrat of California, former Georgia lawmaker Stacey Abrams or former national security adviser Susan Rice.

Biden has entrusted a four-person team to lead his selection process: Former Senator Chris Dodd, of Connecticut; Representative Lisa Blunt Rochester, Democrat of Delaware; Los Angeles Mayor Eric Garcetti; and Biden’s former White House and Senate counsel, Cynthia Hogan.