Paul Johnson, who was detective superintendent with more than 30 years of experience, conducted a domestic homicide review into the deaths of Geraldine and Paul Newman and their two children, Shannon and Shane.
Geraldine and the two children were found dead at their home on Beeston Way on February 2 2016, with Paul's body found at the foot of cliffs in Anglesey, Wales, a few hours later.
The inquest into their deaths at Wakefield Coroner's Court today heard that Paul had killed his family before travelling the 180 miles to Wales and jumping from a 240-foot-high cliff edge.
Mr Johnson said a lengthy investigation into 25 agencies was carried out, but could not find any one of them at fault.
He admitted the marriage of Paul and Geraldine had been 'disintegrating for some years'.
Despite an assault on Geraldine in 2013 which resulted in Paul being sent to prison, they reconciled when he was released.
She had even filled out a self-referral form to say she did not feel physically threatened by him.
However, she did send a text message to a family member in the days leading up to her death saying she was 'terrified' of Paul.
Coroner Kevin McLoughlin asked if Geraldine had been romantically involved with someone else that could have triggered Paul's violence that led to their deaths, but Mr Johnson said there was no evidence, although he was certain that Paul thought she had.
The court was also told that Paul had never admitted to having any thoughts about harming his family.
Mr Johnson said: "There were no glaring missed opportunities.
"There was nothing that could have affected the outcome.
"It’s an absolute tragedy. I did try to find some rationale or reason, but I couldn’t."
The coroner added: “One can only lament that if he had voiced the demons in his mind, it might have precipitated some change.”
His verdict found that Paul Newman had committed suicide and Geraldine and the children were unlawfully killed.