what does " slits of onyx"mean? Bestigui was breathing noisily, but seemed to be pondering Strike’s words. At last he snarled: “There wasn’t any fucking killer. Wilson never found anyone up there. Landry jumped,” he said, with a small, dismissive jerk of his head. “She was a fucked-up little druggie, like my fucking wife.” “There was a killer,” said Strike simply, “and you helped him get away with it.” Something in Strike’s expression stifled Bestigui’s clear urge to jeer. His eyes were slits of onyx as he mulled over what Strike had said. “I’ve heard you were keen to put Lula in a film?” Bestigui seemed disconcerted by the change of subject. “It was just an idea,” he muttered. “She was a flake but she was fucking gorgeous.” “You fancied getting her and Deeby Macc into a film together?” “License to print money, those two together.”