A British cybersecurity expert accused of creating and distributing malware designed to steal banking passwords is headed to court for a hearing on what evidence may be used in the case.

Marcus Hutchins was credited with stopping the worldwide WannaCry computer virus before he wound up being charged in the case.

Federal prosecutors in Milwaukee say Hutchins acknowledged in recorded jailhouse phone calls that code he wrote wound up in malware, and they want to introduce that evidence. Attorneys will argue the matter Wednesday.

Robert Graham, a computer security expert not connected to the case, warned against concluding that Hutchins did something wrong simply because his code wound up in malware.