DENVER -- The family of the man prosecutors said was murdered to silence his testimony told a jury that he knew the danger, but insisted on testifying.

Javad Marshall-Fields and his fiancée, Vivian Wolfe, were ambushed while driving their car in Aurora in June of 2005.

Marshall-Fields was set to testify in an upcoming trial involving the murder of his friend Greg Vann.

Hours before the shooting, Marshall-Fields told his uncle and sister that he was scared and worried that his life was in danger. He said he had been approached at a sports bar and told to "watch his back." In spite of the danger, he said he was going to testify.

"He was the only one who said, 'I am going to stand up for the truth.' It makes me proud to be his sister," his sister told 7NEWS.

Sir Mario Owens is accused of killing the couple. He could get sentenced to death if he is convicted in this case.