The man was pronounced dead at the scene while the 10-year-old girl died later in hospital.
The 21-year-old student’s body was found in the Humber Estuary last week.
Libby Squire has been missing for more than a month.
The student went missing in the early hours of February 1.
While sentencing Jamie Nickell, Judge Mark Bury said: 'Homelessness is a necessity, unhappily, for some members of our society'
The video footage is the the last confirmed CCTV of the 21-year-old on the night she disappeared.
University of Hull student Libby Squire, 21, has not been seen since the early hours of Friday.
Libby Squire was reported missing from Hull in the early hours of Friday morning.
Lisa and Russell Squire, whose daughter Libby has been missing from her home in Hull since Friday, have made an emotional appeal.
Libby Squire was reported missing after getting into a taxi outside a Hull nightclub on Thursday night.