Keep you close : a novel / Lucie Whitehouse.

Enhanced descriptions from Syndetics:

When the artist Marianne Glass falls to her death, everyone insists it was a tragic accident. Yet Rowan Winter, once her closest friend, suspects there is more to the story. Ever since she was young, Marianne had paralyzing vertigo. She would never have gone so close to the roof's edge.

Marianne--and the whole Glass family--once meant everything to Rowan. For a teenage girl, motherless with a much-absent father, this lively, intellectual household represented a world of glamour and opportunity.

But since their estrangement, Rowan knows only what the papers reported about Marianne's life: her swift ascent in the London art world, her much-scrutinized romance with her gallerist. If she wants to discover the truth about her death, Rowan needs to know more. Was Marianne in distress? In danger? And so she begins to seek clues--in Marianne's latest work, her closest relationships, and her new friendship with an iconoclastic fellow artist.

But the deeper Rowan goes, the more sinister everything seems. And a secret in the past only she knows makes her worry about her own fate . . .