She directed the Netflix documentary movie, Into The Deep, which began as a chronicle of Danish inventor Peter Madsen’s life and work, but evolved into something more sinister when Madsen was suspected of, convicted, and subsequently imprisoned for the murder of Kim Wall, a renowned Swedish journalist.

The footage shot by Sullivan for the documentary was thoroughly examined and utilized by the prosecution to put Madsen behind bars. In 2018, he was sentenced to life imprisonment for the crime.