Soham detective Brian Stevens has been challenged in court over his claim that he told Jessica Chapman's family she had been found dead.
Brian Stevens denies conspiring to pervert the course of justice
Mr Stevens, 43, is on trial at the Old Bailey for conspiring to pervert the course of justice in an unrelated case.
He choked back tears on Wednesday, saying breaking the harrowing news to the Chapmans was part of his role as their family liaison officer.
But prosecutors said a female officer had broken the news to the family.
Mr Stevens' lawyer, Godfrey Carey QC, had asked him "Your tasks included the duty of telling them their daughter had been found dead?" and Stevens dabbed his eyes with a handkerchief as he replied "Yes it did sir."
'I will never forget it'
But on Thursday, prosecutor Peter Joyce QC ushered Pc Gaye Mallows into court and said that it was she who told the Chapmans.
Mr Joyce suggested to the defendant that he and Pc Mallows had been in the Chapman's garden when she received a telephone call in the early hours of 17 August and took the parents into the house on her own.
He said Pc Mallows later told Mr Stevens and the girl's grandfather the news.
But Mr Stevens said that it was he who told Mrs Chapman that her daughter was dead, based on forensic evidence uncovered in the case, on a different occasion.
He said: "I will never forget that sir, that's indelible on my mind and I will never forget it."
An anxious time
Mr Stevens was suspended by Cambridgeshire Police after he was alleged to have downloaded pornographic material on his laptop computer.
The family liaison officer has said he had been suffering a great deal of "anxiety and confusion" and had considered suicide.
Prosecutors offered no evidence against him at Snaresbrook Crown Court in London in August 2003.
But he was arrested again and accused along with his friend, Louise Austin, 32, an executive case officer for the Crown Prosecution Service, of concocting a false alibi for the times when the images were alleged to have been downloaded.
Mr Stevens and Miss Austin both deny conspiring to pervert the course of justice.