Linwood Nelson

Linwood Nelson, a Vietnam War veteran, was infected with hepatitis C by David Kwiatkowski during a procedure at Baltimore VA Medical Center. Kwiatkowski has been arrested for spreading the disease by using and replacing needles at a hospital where he worked in New Hampshire. (Algernia Perna, The Baltimore Sun / November 4, 2012)

According to the affidavit, nurses often remove the vials and draw the medications into needles at the beginning of a procedure so they are ready for use. The needles are then labeled.

Co-workers, including a lab supervisor, told investigators that Kwiatkowski would spend more time near the nurses' station than other technicians, would enter the lab during procedures that he wasn't scheduled to assist on, and would at times place lead radiation aprons on a table near the Pyxis machine after nurses had filled needles from vials.

Investigators were also told the lab is usually dark during procedures so physicians can read video screens above patients.

"The Supervisor speculated that upon setting the lead apron on this table, Kwiatkowski may have been able to take a syringe containing fentanyl and replace it with a tainted syringe containing saline or another substance," DiFede wrote. "The Supervisor also said there would be no reason for a technician to be in the nursing area where the medications are located. He noted that it was unusual for an employee to bring in lead aprons for other employees."

It's unclear what consequences were experienced by patients who were prescribed fentanyl but injected with something else.

Those interviewed said syringes labeled as having contained fentanyl were found multiple times outside the lab — once by a patient's relative in a public bathroom.

During a search of Kwiatkowski's car in June, federal investigators found an empty syringe with a blue sticker reading "fentanyl" that appeared to be "consistent" with the stickers used to label needles at Exeter, according to the affidavit.

Some Maryland hospitals where Kwiatkowski worked say they have different control procedures in their labs — for example, requiring that drugs only be drawn into syringes right before use on a patient, and that drugs never be left unattended. They hope those procedures have limited the possibility that their patients might have been infected by Kwiatkowski.

Kwiatkowski faces up to 24 years in prison on the charges, as well as fines of up to $500,000 and a term of supervised release, according to New Hampshire U.S. Attorney John P. Kacavas' office.