PHOENIX (AP) — A judge has rejected a bid to throw out DNA evidence against a man charged with sexually attacking and fatally stabbing two young women in separate attacks in the early 1990s while they were riding bikes near a canal system that winds through metro Phoenix.

Lawyers for Bryan Patrick Miller argued police violated his rights because they didn’t have a warrant when collecting his DNA from a mug at a restaurant where he met with an undercover officer.

Authorities say DNA collected from the 2015 dinner linked Miller to the deaths of 22-year-old Angela Brosso in November 1992 and 17-year-old Melanie Bernas in September 1993.

In a ruling two weeks ago, Judge Suzanne Cohen explained Miller had no reasonable expectation of privacy for DNA left on a mug after he left the Chili’s Grill & Bar location. “Customers who walk to a restaurant’s exit, having left such items behind, implicitly communicate their intent to abandon them,” Cohen wrote.

Brosso and Bernas disappeared in north Phoenix near the Arizona Canal. Brosso was found nude and decapitated in a field near a bike path that’s adjacent to the canal.

Ten months later, Bernas’ body was discovered floating in the canal. Authorities said semen evidence collected in the aftermath of both crimes showed the attacks were linked to the same suspect.

The killings faded from public attention after police were unable to link the DNA profile collected from the scenes to a specific suspect. The Phoenix Police Department’s cold-case unit was on the cases again in 2011, according to court records.

In 2014, a genealogist who uses ancestry databases in her research was given access to the DNA gathered in the investigations and eventually came up with the last name Miller. Bryan Miller had been on the police department’s list of investigative leads in the case, according to court records.

That led police to contact Miller to set up the dinner at the restaurant. The undercover officer posed as a security company employee trying to enlist Miller’s help in conducting surveillance at a business located near Miller’s employer.

Police said Miller denied any involvement in the killings but acknowledged living in the vicinity of the killings at the time and said he rode his bike on bike paths in the area. They said he was unable to explain how his DNA matched the evidence found at the crime scenes.

A phone message left for his attorney, Richard J. Parker, wasn’t immediately returned.

Miller has pleaded not guilty to charges of murder, kidnapping, sexual assault and attempted sexual assault. Prosecutors are seeking the death penalty.

His trial is scheduled for Sept. 21.

Authorities have said Miller was charged with but ultimately acquitted in the 2002 stabbing of a woman in Everett, Washington, after saying the woman tried to rob him.

The Washington state case didn’t require him to submit a DNA sample because he was acquitted. He later moved back to Arizona.