The Iowa Republican’s letter to the company cites findings from a series of Wall Street Journal articles.

The Wall Street Journal says the Justice Department in recent months has launched a new investigation into UnitedHealth Group’s billing practices as a civil fraud investigation looks at the use of diagnosis data to trigger extra payments to the company’s Medicare Advantage plans.

The probe is analyzing the company’s practice of frequently logging diagnoses that trigger larger payments to its Medicare Advantage plans, according to a report.

D: Noon on Feb. 21The Department of Justice is probing UnitedHealth Group's billing practices in Medicare Advantage, according to a report from the Wall Street Journal. | The Department of Justice is probing UnitedHealth Group's billing practices in Medicare Advantage,

UnitedHealth Group called The Wall Street Journal's report "misinformation" and said it was unaware of reported investigaiton.

The Iowa Republican’s letter to the company cites findings from a series of Wall Street Journal articles.