Sharon Shoesmith oversaw a "deeply flawed" disciplinary process which concluded that two social workers involved in Baby P's care should not be sacked, an employment tribunal has heard.
Gillie Christou and Maria Ward were fired by Haringey Council in north London for "gross misconduct" after a second investigation found they committed serious failings in protecting the vulnerable child.
They claim they were unfairly dismissed following public outcry about the toddler's death aged 17 months in Tottenham, north London, in August 2007.
The pair's mistakes were exposed only after Ms Shoesmith was herself dismissed as Haringey's director of children's services over the tragedy in December 2008, the tribunal was told.
Ms Ward, 40, was baby Peter Connelly's nominated social worker and Mrs Christou, 52, was her team manager.
Stuart Young, an assistant chief executive at Haringey Council, told the tribunal that graver failings they made in Peter's care were known to senior managers at this time.
"It was only when I looked at the cases following Ms Shoesmith's dismissal in December 2008 that I became aware of the deeply flawed nature of the disciplinary investigations and hearings that had taken place in or around May 2008," he said in a witness statement.
Mr Young led Haringey's second inquiry into Mrs Christou and Ms Ward's conduct in Peter's case, which resulted in their sacking in April last year.
Referring to the more serious errors that led to Ms Ward's dismissal, he said: "It's clear that the issues that formed the basis of my allegations were known to senior managers within the children's service in May 2008. Those issues should have been the subject of disciplinary action at that time."
The tribunal also heard Ms Shoesmith employed Haringey's "simplified" disciplinary procedure for the first investigation into Mrs Christou and Ms Ward, which was normally used in simple cases where employees admitted misconduct.