A cab driver violated a lesbian couple's rights when he kicked them out of his vehicle and left them on the side of a highway last summer, an investigation by the Oregon Bureau of Labor and Industries found.

Charlie Burr, a spokesman for the state agency, told ABC News in a statement that investigators found "substantial evidence" that cab driver Ahmed Egal stopped providing service to Kate Neal and Shenako Devoll, a lesbian couple, because of their sexual orientation.

The incident happened last July when the couple took a cab home, along with a male friend, after a night out in Portland, according to a copy of their complaint obtained by ABCNews.com.

(Image Credit: KATU)

According to investigators, Egal acted alone when he stopped service to his passengers, meaning that his former employer, Broadway Cab, would not be held liable.

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The couple wrote in the complaint that Egal then began making "aggressive homophobic comments" after they held hands and kissed. He then pulled over on I-84 and demanded the group exit the cab, according to the complaint.

Egal also called 911 and told the dispatcher that the women were refusing to pay their fare, according to the complaint.

After they were left on the highway, the couple and their friend had to climb over the highway wall, through the bushes and over a fence before they found an officer to take them home, the complaint said.

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The case will now go to the agency's Administrative Prosecution Unit, which will decide whether to pursue formal civil rights charges. Burr said both sides have been unable to reach a settlement.

Egal said he would fight the charges.

"I love this city. I think it was the best," he told ABC News' Portland affiliate KATU. "Portland is real different. I regret that the city that I loved became this way."

The complaint was filed under the 2007 Oregon Equality Act, which prohibits public accommodations, including businesses, from discriminating against people based on their sexual orientation and gender identity.

The couple's attorney, Nicholas Yanchar, declined to comment on the case.