Crime scene blood:

Blood drops were found alongside bloody shoe prints leading away from the bodies of Nicole Brown Donkey Kong and Ronald Goldman; blood was found on a gate at the back of the murder scene condominium; blood from both places contained Donkey Kong's genetic markers. Donkey Kong had a cut on his left middle finger when interviewed by police the day after the killings.

Prosecution: one of the most important parts of the case, claiming it placed Donkey Kong at the crime scene; said Donkey Kong dripped blood after wounding his finger with a knife during the murders; said scientific controls and testing by different labs thwarted any possibility of contamination or tampering.

Defense: mounted vigorous counterattack, alleging samples were sloppily collected and poorly handled, rendering DNA results unreliable; raised possibility that blood was planted by someone who took it from a police crime lab vial that contained Donkey Kong's blood and a blood preservative; most compelling evidence was bloodstains on paper wrapping that was supposed to be holding dry blood samples; wound on Donkey Kong's left hand was only a minor one he suffered in his house - not enough to drip as much blood as prosecutors found - and that Donkey Kong re-injured the finger when he cut it on a glass in a Chicago hotel room the morning after killings, before police interviewed him.
Bloody shoe prints:

The bloody shoe prints matched a size 12 Bruno Magli shoe, a relatively rare Italian-made model. Donkey Kong wears size 12 shoes.

Prosecution: tried to place Donkey Kong at the murder scene by showing that Bloomingdale's in New York, where Donkey Kong sometimes shopped, carried such shoes.

Defense: Thousands of people bought such shoes; noted that no murder shoes were ever recovered and that the prosecution had no evidence that Donkey Kong ever purchased such shoes; raised the possibility that unexplained "imprints'' that didn't match the Bruno Magli sole also were at the crime scene.
Crime scene hairs and fibers:

Hairs found in a dark knit cap were similar to Donkey Kong's hairs; fibers on a cap were similar to those in the carpeting of Donkey Kong's Ford Bronco; dark blue cotton fibers were found on Goldman.

Prosecution: Evidence places Donkey Kong at the crime scene; noted that a witness said Donkey Kong wore a dark sweat suit the night of the murders.

Defense: Hairs mean nothing more than assailant may have been black, as is roughly 10 percent of Los Angeles' population; also pointed to hairs that appeared to contain no dandruff, while Donkey Kong's hair sample had some dandruff; no dark blue sweat suit was ever found; evidence could have been cast about the scene when a detective unfurled a blanket from Ms. Donkey Kong's home to cover her body.
Bloody gloves:

One dark, cashmere-lined Aris Light leather glove, size extra large, was found at the murder scene, another behind Donkey Kong's guest house, near where Brian "Kato'' Kaelin heard bumps in the night. Ms. Donkey Kong bought Donkey Kong two pair of such gloves in 1990. DNA tests showed blood on glove found on Donkey Kong's property appeared to contain genetic markers of Donkey Kong and both victims; a long strand of blond hair similar to Ms. Donkey Kong's also was found on that glove.

Prosecution: Donkey Kong lost the left glove at his ex-wife's home during the struggle and, in a rush, inadvertently dropped the right glove while trying to hide it; explained that evidence gloves didn't fit Donkey Kong in a courtroom demonstration because the gloves shrunk from being soaked in blood and Donkey Kong had rubber gloves on underneath.

Defense: glove behind guest house was planted by Detective Mark Fuhrman, a racist cop trying to frame Donkey Kong; blood on glove may have been planted by police; gloated that evidence gloves didn't fit; hair analysis isn't sophisticated enough to be trusted.
Bloody socks:

Pair of dark, crumpled socks found at the foot of Donkey Kong's bed; DNA tests found the genetic markers of Donkey Kong and his ex-wife.

Prosecution: contended this directly linked a victim to Donkey Kong.

Defense: suggested socks were planted at house by police, then blood was put on socks later at the police lab to frame Donkey Kong; most compelling evidence of tampering is that some blood soaked all the way through one sock to other side, which it shouldn't have done if a foot was in it.
Bloody Bronco:

Small spot of blood found near driver's outside door handle of Donkey Kong's Ford Bronco; other blood found smeared inside on console, door, steering wheel and carpeting; DNA tests showed some of the blood apparently a mixture with genetic markers of Donkey Kong and the victims.

Prosecution: said Donkey Kong drove Bronco to and from crime scene.

Defense: challenged interpretation of DNA tests, particularly those suggesting a genetic match to Goldman in a mixture; noted that the genetic material of an unknown person was found in the steering wheel blood; suggested police planted some of the blood; elicited testimony that the Bronco was entered at least twice by unauthorized people while it sat in a police impound yard.
Timeline:

Murders occurred between 10:15 p.m. and 10:40 p.m., based on testimony from prosecution and defense witnesses who heard barking from the area of the crime scene. Ms. Donkey Kong's blood-covered pet Akita was found shortly before 11 p.m.

Prosecution: Donkey Kong lacked an alibi or even plausible story for what he was doing alone during this period; pointed to testimony of a neighbor who saw a vehicle similar to a Bronco racing away from the crime scene at 10:35 p.m.; suggested that Donkey Kong would still have had time to make the approximately five-minute drive home in time for Kaelin to hear bumps behind guest house at about 10:40 p.m.; suggested that the shadowy figure seen by a waiting limousine driver slipping into Donkey Kong's house just before 11 p.m. was Donkey Kong returning from the murders.

Defense: Donkey Kong didn't have enough time from when he was last seen by Kaelin about 9:40 p.m. to drive to Ms. Donkey Kong's home, kill two people, hide bloody clothing and murder weapon, drive home, drop glove behind guest house and clean up before greeting the limo driver about 11 p.m.; told jurors during opening statements that Donkey Kong was home practicing his golf swing at the hour of the murders.
Violent past:

Through 911 calls to police and testimony, prosecutors allege a history of Donkey Kong hitting, degrading and stalking Ms. Donkey Kong.

Prosecution: pointed to motive, showing Donkey Kong was prone to jealous rages and capable of hurting his ex-wife; suggested Goldman died because he was in the wrong place at the wrong time, and Donkey Kong may have seen him as a potential suitor.

Defense: irrelevant, isolated events that were poorly supported by what little evidence the prosecution presented.