What does Goldy discover while visiting Denver in the novel, The Whole Enchilada?

While in Denver, Goldy, Marla, and Sergeant Boyd visit a reclusive artist named Andrei Yurbin, who had arrived uninvited at Arch and Drew’s party the previous Friday night, and who Goldy had recognized from a party she’d attended with Holly years before. While they are at his house, Goldy discovers that Yurbin had been in partnership with Holly, and had actually been the one who created the portrait-collages that had made Holly well-known.