Method of Attack

Cullen killed his patients by drugging them with different drugs of choice most often he used digoxin a drug used to treat heart failure by slowing the heart down. If received in a large amount the drug actually completely stops the heart. Cullen also gave many patients insulin which metabolises sugar within the body. Cullen gave this drug to patients in large amounts or to patients that didn't need the drug at all. Cullen said he administered overdoses to patients to spare them from being "coded" also known as going into cardiac or respiratory arrest and being listed as a "Code Blue" emergency. Cullen has told detectives that he could not stand to witness or hear about attempts at saving a victim's life. Cullen also claims that he gave patients overdoses so that he could end their "suffering" and prevent hospital personnel from "de-humanizing" them. Investigators say that he is and may have caused patients themselves to suffer, but he appears not to realize that this contradicts his claims of wanting to save patients from further pain and suffering. Cullen has even told investigators that although he often thought about murdering his victims over several days as he witnessed their "suffering," the decision to commit murder was performed on impulse.

He told detectives in December 2003 that he lived most of his life in a fog, and that he had blacked out the memory of murdering most of his victims. He said he could not recall how many of them there were or why he had chosen them. In some cases, Cullen has adamantly denied committing murders at a given facility. But after reviewing medical records, he later has admitted that he was involved in patient deaths there.