A serial killer convicted back in the 1980s partially won his appeal in the Supreme Court of Guam. 

Eligio Adriatico is serving a life sentence, which he contends was illegal. 

Justices ruling at the time of his sentencing, Guam law did not permit life without parole for attempted aggravated murder.

The case was remanded to the Superior Court for further proceedings. 

As KUAM reported, Adriatico was 20-years-old back in 1983 when he and co-conspirator Romeo Marquez went on a crime spree that took seven lives and injured ten.

The pair again took two lives inside the Department of Corrections.

Adriatico is currently being held in a federal prison in Atwater, California.