The sister of a good Samaritan killed in a hit and run on Anthony Henday Drive two years ago says she's still in a state of disbelief.

"I was devastated," said Clarine Hightower. "I really sometimes just kind of block it out of my memory and just think that it's just a dream."

Hightower arrived in  Edmonton today from her home near Washington D.C. for the third day of the trial of Kieran Porter, who is accused of killing Andrew Green as he changed a tire for a driver stranded on the Henday ring road.

The court is considering whether critical information given by Porter to an insurance company should be allowed as evidence.

Porter told insurance company employees that he dropped his cigarette while driving and looked down to find it when he hit something — he wasn't sure what.

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Andrew Green, 46, was killed while helping a stranger change a tire on the Henday. (Facebook)

In an audio recording with an employee, he was heard saying that the entire right front side of his Porsche was damaged, but he didn't stop.  

He told the employee he only realized he may have hit a person the next day when he heard about a hit and run on the news.

He also refused to answer some questions, including one regarding the use of drugs or alcohol before driving that night.

The defence is challenging the evidence on constitutional grounds, arguing Porter wasn't told he was being recorded.

Hightower said she just wants justice.

"I really can't for the life of me believe that this has happened to someone in our family."

Porter has pleaded not guilty to careless driving and failing to stop and offer help to an injured person.

The judge will hear arguments about whether the information can be used as evidence next week.

With files from CBC's James Hees