A DETECTIVE who led a "flawed" investigation which failed to catch serial killer Harold Shipman was today being quizzed by the inquiry into the former GP's crimes.

Det Insp David Smith was selected to lead the March 1998 investigation after a fellow doctor voiced concerns about Shipman's high death rate.

But after a "discreet" and "confidential'' four-week-long investigation, Det Insp Smith decided the respected family GP -- evenutally convicted of killing 15 of his patients -- had done nothing improper and the case was dropped.

Shipman - who was convicted of killing 15 elderly women but who is suspected of killing hundreds more with heroin injections - went on to kill three more women before being caught.

Today, Det Insp Smith was due to step before the cameras at Manchester Town Hall to give evidence as part of the second - and televised - phase of the Shipman Inquiry.

Public hearings for Phase One of the inquiry are already complete and chair Dame Janet Smith has promised to publish decisions on around 500 Shipman patients in her interim report in July.

Earlier this month, Greater Manchester Police offered their "regrets" to the families of Shipman's victims, adding that the "strategic management" of the case had been "flawed".

The investigation was "terminated prematurely" in April 1998, said Michael Shorrock QC, for GMP.

In the following five months before Shipman's arrest, he killed Winifred Mellor, 73, Joan Melia, 73, and Kathleen Grundy, 81.

Det Insp Smith's evidence is expected to last three days.

Shipman is currently serving life at Frankland Jail, Co Durham, after being convicted of 15 counts of murder at Preston Crown Court in January 2000.