PORTLAND, Ore. (AP) — An Oregon judge has thrown out statements made by a man accused of killing four women, finding that Portland police used improper and coercive tactics during the interrogation.

The Oregonian/OregonLive reports that 57-year-old Homer Lee Jackson was arrested in October 2015 in connection to strangling deaths that occurred in the 1980s.

Police questioned Jackson for more than seven hours over two days.

Judge Michael A. Greenlick suppressed the statements that authorities say were a confession by Jackson.

The judge says that the types of inducements or threats made by police can create a risk of an inaccurate admission.

Prosecutors say the statements were given voluntarily and the detectives did not make threats.

Jackson has pleaded not guilty to aggravated murder charges.