Buried secrets - Joseph Finder

When private investigator Nick Heller returns home to Boston to set up his own agency, he soon gets an urgent case closer to home than expected.
Alexandra Marcus - teenage daughter of hedge fund titan and Heller family friend Marshall Marcus - has been kidnapped. But it's no ordinary kidnapping - she has been abducted by professionals, buried alive in an underground casket, a video camera streaming her desperate pleas live over the internet. With a limited supply of food and water, time is quickly running out.
Nick is determined to catch the perpetrators but when Marcus is arrested by the FBI for fraud, accused of operating a Ponzi scheme, Nick realises that he has some powerful enemies who may have the motivation to go after his daughter and a conspiracy that reaches up to the very highest levels of government. Nick must play a dangerous game if he hopes to flush out those responsible before Alexa is buried for good...