Pudsey murders: Chief Constable's 'sadness' over deaths
West Yorkshire's Chief Constable, Sir Norman Bettison, has described the deaths of a couple and their two sons as "a real tragedy".
Clair Smith, 36, and her sons Ben, nine, and Aron, one, were found stabbed at their home in Pudsey on Sunday. Mrs Smith's husband, Richard, 37, had died from smoke inhalation.
They were found in a fire-damaged bedroom in house on Sheridan Way.
Police are not looking for anyone else over the deaths.
The results of a post-mortem examination revealed Mrs Smith had died from a single stab wound, as did baby Aron.
Ben Smith had suffered a stab wound to the chest area, but died as a result of suffocation.
Sir Norman said the nature of their deaths was "not unique, but it is unusual".
He said: "It is something that still shocks us as a society and a community.
"For something like this to happen in the midst of Pudsey is a real tragedy for all concerned."
Sir Norman said the police investigation into the four deaths would "take as long as it needs".
Janet Howard, head teacher of Greenside Primary, the Pudsey school which Ben Smith attended, said staff and pupils were "in shock and deeply saddened".
"Ben was a wonderful, bright pupil who thoroughly enjoyed coming to school," she said.
"He loved to help others, was a member of our school council, and was a really popular boy, not just with his friends but across the school."