A not guilty plea has been entered by a 55-year-old man linked to at least four deaths in Portland dating back to the 1980's.

Homer Lee Jackson is accused of killing four women who were linked to prostitution between 1983 and 1987. Forensic evidence linked him to the four, and he is believed to be possibly responsible for at least twelve murders.

Jackson apparently "self-reported" that he was paranoid and suffered from schizophrenia, and was diagnosed as such in 2011.

The investigation remains open, and now that news has spread of the charges, other women with connections to Jackson are coming forward with new information.

Jackson was well known to authorities, having been charged with various crimes including burglary and criminal mischief, dating back to 1983 in Multnomah County. He is being held in the county jail without bail.