"No jury has sacrificed more for the pursuit of justice and I want to thank you for your selflessness and devotion from the bottom of my heart," she said.
She urged them not to be distracted by "many false roads" that the defence had opened: "I submit to you that we have met more than our burden of proof on this issue," she said.
She then tackled the issue of Detective Mark Fuhrman, the prosecution witness who said he found a bloody glove in the grounds of Mr Simpson's house and was proved a liar when he said he had not used racist language. "It would be wrong to find Simpson innocent because of the anger and disgust toward Fuhrman," she said."Did he lie when he said that he had not used a racial epithet in the last 10 years? Yes.
"Is he a racist? Yes.
"Is he the worst the LAPD has to offer? Yes."
The prosecution conceded that the Los Angeles police had both sloppy forensic scientists and coroners. Whatever their failings, Ms Clark declared, the evidence in the case had not been contaminated or planted.
The prosecution then launched into a detailed review of events on the night of the murders. Ms Clark portrayed Kato Kaelin, Simpson's house guest, as an unbelievable prosecution witness who had been coerced into providing an alibi.
Between 9.36, when Simpson and Kaelin returned from MacDonald's, and10.54, when the defendant answered an intercom call from Allan Parks, a limousine driver hired to drive him to the airport, his movements could not be accounted for, she said.
However, records of his mobile telephone showed that Mr Simpson was out in his Ford Bronco at 10.03.The murders, she said,occurred 10 or 15 minutes after that call.
In preparation for an attack on Mr Simpson's alibi - that he was practising his golf swing at the time of the murders - Ms Clark said that Mr Parks had been unable to get a response from Mr Simpson's Rockingham estate until 10.54 - after he had seen a dark figure with the same height and build as Simpson approaching the front door of the house.
When he saw lights in the house come on he called on the intercom again.This time Mr Simpson answered saying he had overslept and was taking a shower.
Ms Clark's closing argument has introduced new evidence that appears to show Mr Simpson was out in the Bronco; that Allan Parks did not see the Bronco in the alley, where it was subsequently found by police, when he tried a side entrance, and when Simpson finally appeared to leave for the airport he went twice in the direction of the alley, apparently to collect the cellular phone.
The summing up of the case is expected to last until the end of next week.