Shakiel Shazad, a man who killed eight members of the same family in an arson attack has gone on the run from prison in Derbyshire.
The 33-year-old was sentenced to 18 years in prison in 2003 for his part in the blaze in Huddersfield, along with two other men.
Derbyshire Police said Shazad was released from Category D Sudbury Prison, near Uttoxeter, yesterday on a work licence.
The force said he is "now unlawfully at large".
A spokesman said: "He has connections in Huddersfield, West Yorkshire.
"Anyone with any information about the whereabouts of this man is asked not to approach him but to immediately contact their local police or Crimestoppers anonymously 0800 555111."
Seven members of the Chishti family - Muhammad Ateeq-ur-Rehman, 18, Nefeesa Aziz, 35, Tayyaba Batool, 13, Rabiah Batool, 10, Ateeqa Nawaz, five, Aneesa Nawaz, two, and six-month-old Najeeba Nawaz - died in the fire in May 2002.
Another family member, Zaib-un-Nisa, 54, died in hospital a week later.
Three men - Shazad, Shaied Iqbal and Nasar Hussain - were convicted for their part in the crime.
A fourth man, Shaid Mohammed, was arrested by police after the blaze but went on the run and has never been captured.
Shazad is Asian, 5ft 6in, with short black hair, a black beard and brown eyes.