What were the problems with the physical evidence in the O.J. Simpson investigation?

The Los Angeles Police Department was implicated in several procedural errors that undermined the credibility of physical evidence in the 1995 murder case The People of the State of California v. Orenthal James Simpson. Errors included a failure to secure and protect the crime scene where the murders of Nicole Brown and Ron Goldman took place, mishandling of evidence, and accusations of evidence tampering. The two most controversial pieces of physical evidence were the leather gloves and the blood samples.
The gloves: one left glove was found at the crime scene and its match was found at Simpson’s home. The left glove was covered in blood that fit the DNA profiles of Simpson and both victims. Simpson was known to wear the same brand and style of gloves.
The problems: (1) The right glove was recovered from Simpson’s home by Detective Mark Fuhrman after Fuhrman climbed a wall to investigate the property. Over the course of the trial, Fuhrman’s credibility was compromised by accusations of racism. He denied the accusations until recordings surfaced of him using racial slurs referring to African Americans. When he was asked under oath whether he tampered with or planted physical evidence, he invoked the Fifth Amendment, refusing to answer the question. (2) Against the wishes of lead prosecutor Marcia Clark, co-prosecutor Chris Darden requested that Simpson try the gloves on during the trial. They were too small. In perhaps the most famous moment in modern trial history, defense attorney Johnnie Cochran told the jury to remember, “if it doesn’t fit, you must acquit.” Other than Simpson’s innocence, theories about why the gloves didn’t fit have included shrinkage from being soaked in blood or a similar effect from the storage or analysis processes. The latex gloves Simpson wore when he handled the leather gloves during trial may have prevented them from fitting as they otherwise would have.
The blood: blood was found throughout the crime scene, in Simpson’s Ford Bronco, on the gloves, on a pair of socks, and at Simpson’s home.
The problem: (1) Like the right glove, Detective Mark Fuhrman found the socks and the blood in the Bronco. (2) Several blood spots found at the crime scene were documented but never sampled. (3) Blood-covered items collected at the crime scene were mishandled. Some items were placed together in the same bag, which could have cross-contaminated them. Some items were bagged while wet, which could have affected the results of forensic analysis. Some items were handled without gloves. (4) Due to the LAPD’s procedural errors, bloody shoe prints were spread throughout the crime scene by investigators. (5) EDTA, an anticoagulant used when taking blood samples, was present during the analysis of some items of physical evidence. The defense argued that this meant the blood was planted on the items from a sample drawn from Simpson. The prosecution argued that the EDTA was either naturally occurring (it’s found in small amounts in human blood), or it was accidentally introduced during analysis. (6) The amount of blood drawn as a sample from Simpson was not recorded, and some was missing from the vial. (7) The glove had a large quantity of blood on it, but no blood surrounding it. The defense argued that it was planted because otherwise there would have been a trail.
At the time of Simpson’s trial, DNA analysis had been used in court cases for less than a decade and was still a largely incomprehensible science to jury members and lawyers alike. Testing methods and public understanding have greatly evolved in the intervening years, and it is unlikely that Simpson would be exonerated today given the preponderance of blood evidence.