Updated

Authorities say a Maryland man was paying people to draw their blood and storing the blood in large quantities in an abandoned apartment in Washington.

The Washington Post reports 43-year-old Khoa Hoang Nguyen was charged with practicing registered nursing without a license.

The report says officers saw "habitual substance abusers" standing in front of an apartment building Wednesday, and some were talking about being paid to give blood. Inside one of the apartments, a woman told police she and Nguyen had drawn blood from 20 people that day. Nguyen also had a ledger with an additional 205 names. Nguyen said he worked for a biomedical company and was certified to draw blood, but authorities weren't able to corroborate that.

Nguyen declined to comment Thursday after his first court appearance.