Juanito Rostagno was the proprietor of the Mano de Dios Amber Mine inJurassic Park. Donald Gennaro arrived to speak to him on behalf of InGen's investors concerning the whereabouts of Hammond at a time when InGen was being sued by the family of a worker who'd been killed by a Velociraptor. In response to Gennaro's claim that the investors would want an inspection of the park, Rostagno insisted Hammond wouldn't like the idea because Hammond hated inspections.
Even when a worker came to inform them that they'd found a new piece of amber with a fully preserved mosquito inside, Gennaro, following Rostagno into the mine, pressed the issue and said his clients wanted Alan Grant to sign off on Jurassic Park. Ian Malcolm was "too trendy." A skeptical Rostagno told him they'd never get Grant away from his current dig in Montana, apparently underestimating how persuasive Hammond could be.