One of the 30 people believed to have contracted hepatitis C from a traveling medical technician in New Hampshire is suing a Nebraska-based health staffing agency.

Robert Fowler of Seabrook was diagnosed with the blood-borne viral disease in June, 14 months after he underwent a cardiac catheterization at Exeter Hospital. Fowler was treated at the hospital’s cardiac lab a month after it hired David Kwiatkowski, who was charged last week with federal drug crimes.

Kwiatkowski is accused of stealing anesthetic drugs from the lab, injecting himself and contaminating syringes that were later used on patients.

Though he told investigators he was diagnosed with hepatitis C in May, authorities said there is evidence that he has had the disease since at least June 2010.

In a lawsuit filed Sunday in federal court in Nebraska, Boston lawyer Domenic Paolini alleges that Triage Staffing Inc. was negligent in hiring, employing and supervising Kwiatkowski as a traveling technician and in sending him to Exeter. He argues that Triage should have known of the likelihood that Kwiatkowski would cause harm and that the company intentionally misrepresented his qualifications and employment record.

Triage’s president did not return calls seeking comment Friday or Monday.

Kwiatkowski, who grew up in Michigan, worked as a “traveler” sent by staffing agencies to hospitals around the country, usually for temporary jobs. Federal prosecutors say he has worked in at least six states since 2007.

Though authorities have not publicly identified the other states, health officials in Michigan, Maryland, Kansas and New York have confirmed his employment. He worked at Exeter Hospital from April 2011 until May, when he was fired after the outbreak was discovered.

According to court documents, Kwiatkowski told investigators he did not steal drugs, is “not a shooter,” and is scared of needles. He also said he was allergic to fentanyl, the powerful anesthetic he’s accused of stealing, though medical records indicate he was given the drug during a medical procedure in 2011.

Former co-workers in other states told investigators that Kwiatkowski was known for telling false stories, including saying that he had cancer. According to court documents, he was fired for falsifying his timesheets at one hospital, was accused of stealing fentanyl from a hospital operating room in 2008 and aroused significant suspicion in Exeter, where co-workers said he sometimes looked like he was “on something.”

But the head of the cardiac lab said Kwiatkowski provided plausible explanations related to either personal medical issues or family crises whenever co-workers raised questions.