David Matthew Kwiatkowski, 32, who worked at Exeter Hospital, was arrested in Massachusetts and charged with "obtaining controlled substances by fraud and tampering with a consumer product," U.S. Attorney for the District of New Hampshire John P. Kacavas said in a release.
Kwiatkowski is suspected of stealing the powerful anesthetic Fentanyl. He has Hepatitis C and allegedly caused "at least 30 individuals to become infected with the blood-borne virus that can cause serious damage to the liver," the release said.
Kwiatkowski, who worked as a medical technician in the cardiac catheterization laboratory, was seen "leaving the CCL during procedures, sweating profusely, attending procedures on his off-days, and engaging in other suspicious behavior."
"One witness claimed that he appeared to be 'on something' while another witness claimed to have observed 'track marks' on his arms," the release said, adding as a technician he should not have had access to controlled substances such as Fentanyl.
Kwiatkowski is charged with drug diversion -- switching patients' syringes and stealing their drugs -- and infecting patients with Hepatitis C.
"The evidence gathered to date points irrefutably to Kwiatkowski as the source of the Hepatitis C outbreak at Exeter Hospital. With his arrest, we have eliminated the menace this 'serial infector' posed to public health and safety," Kacavas said.
Notable deaths of 2014 [PHOTOS]