The Ninth House by Leigh Bardugo 

Alex was running from trouble and ghosts.  She ended up at a crime scene, having lived with the wrong type of people, into drugs, and all of them dead.  But she was cleared by the police.  While recovering in the hospital, she was approached by a Dean from Yale who understood she saw ‘Grays’ and wanted to offer her a free ride to college if she would assist their Lethe program to oversee rituals the ancient houses were secretly performing, forecasting the stock market, running for public office, writing bestsellers, and other things not quite so ethical.  She’s not exactly a novice at seeing the dead, but she can’t seem to locate a dead girl and several groups, including the cops and her Dean try to warn her off looking into the death.  But she can’t help herself and solving this riddle takes her to the Nile on the other side of the Veil to bonding with a dead man, to showing a magical cure in front of the cop assigned to Lethe, to proving a seemingly harmless immortal is more than she seems.