Jurors in the Babes in the Woods murder trial have been urged to "put right a 32-year injustice".
Prosecutor Brian Altman QC called for Russell Bishop to be found guilty of killing nine-year-olds Karen Hadaway and Nicola Fellows.
Bishop was acquitted of the 1986 murders, but was ordered to stand trial a second time in light of new forensic evidence.
In his closing speech, Mr Altman told jurors: "This defendant walked those two girls to their deaths.
"We ask you to put right a 32-year-old injustice by returning verdicts of guilty."
Nicola and Karen were sexually assaulted and strangled in a woodland den in Wild Park, Brighton, in October 1986.
Within three years, Bishop was jailed for life for the kidnap, sexual assault and attempted murder of a seven-year-old girl at Devils Dyke on the South Downs.
Mr Altman highlighted similarities between the two cases, while defence barrister Joel Bennathan QC asserted there were also differences.
On the 1990 attack, Mr Bennathan said: "They are awful offences, and anyone coming to this who did not have the benefit of Your Lordship's directions would probably think you don't come back from that.
"You don't do what happened to that little girl in 1990 and pop up in a trial and expect a fair trial.
"Once you know what happened in 1990 that will do, that's enough, don't worry about the rest.
"Ladies and gentlemen, we say no."
Mr Bennathan suggested Bishop had cut short his evidence in the trial because he was "wound up" by the prosecutor.
He said: "The 1990 offences are an entirely proper area of questioning but it is also blindingly obvious from the word go it was winding Mr Bishop up."
Likewise, asking Bishop about "deeply personal" love letters to a 13-year-old girl while he was in jail awaiting trial in 1987 was also winding him up, the barrister asserted.
In his cross-examination, Mr Altman had quizzed Bishop about the letters in which he referred to "12 inches".
Mr Bennathan added: "The ultimate question was more or less, 'how big is your penis, Mr Bishop?' Some men resent that question."
Bishop has chosen not to attend court to hear the closing speeches in the trial.
The 52-year-old defendant denies two counts of murder.
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