Sackett was killed in 1970, on the heels of some of the most difficult years of race relations in the U.S.
In his opening statement, prosecutor Jeffrey Paulsen laid out his case against Reed to the jury. He said Ronald Reed conspired to kill the 27-year-old St. Paul police officer -- not because of who Sackett was, but because of what he was.
Paulsen said Sackett was a cop and represented everything defendant Reed hated, including the treatment of African Americans by the "white establishment."
Paulsen said Reed became increasingly militant in the time leading up to the murder, speaking at Black Panther-style meetings at the Inner City Youth League in St. Paul. There was no chapter of the Black Panthers in the city, but Paulsen said Reed was hoping to get one started.
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Paulsen said Reed carried out a plan to shoot a cop as a way to impress national Black Panther leaders.
The prosecution's case relies heavily on Reed's former girlfriend, Constance Trimble. Trimble has admitted she lured officer Sackett with a fake emergency call to police just after midnight on May 22, 1970. She called 911 and asked for help, saying her sister was in labor and about to give birth.
Trimble gave an address, and Sackett and his partner arrived four minutes later. After Sackett knocked on the front door and his partner went around to the back of the house, Sackett was shot, hit in the chest just above the badge. He bled to death outside the front door. The shot came from across the street.
Trimble was charged with Sackett's murder in 1972, but was acquitted.
Still, she spent 18 months in jail because she refused to disclose the name of the person who told her to make the 911 call.
Now, nearly 36 years later, the prosecution says Trimble has agreed to testify that it was Reed who persuaded her to make the fake 911 call.
Prosecutor Paulsen says Trimble is coming forward now because she has terminal stomach cancer, and since she's already been tried and acquitted, she has nothing to lose.
Paulsen says two other key witnesses will also testify against Reed. One of them is Joseph Garrett, a former military sharpshooter who met Reed at one of the Black Panther-style meetings. Paulsen told the jury Reed asked Garrett if he wanted to be part of something big, if he wanted to "bring down the first pig" -- a derogatory term for a police officer.
Prosecutor Paulsen says the case is not about Reed's political views or right to free speech. Rather, he says Reed crossed the line between free speech and violent action.
Paulsen said the prosecution is not trying to prove that Reed is the shooter, though he says there is evidence that Reed did shoot and kill Sackett.
Instead, Paulsen told the jury they must decide whether Reed is guilty of aiding, abetting and consipiring to commit murder in the first degree. The charge carries a sentence of life in prison.
Ronald Reed sat quietly in the courtroom looking distinguished, wearing wire-rimmed glasses, a wool suit and tie.
Reed's attorney John Peccia told the jury his client is not guilty. He said the prosecution's case is weak because there are no eyewitnesses, and no weapon was ever found.
Peccia told the jury to be suspicious of prosecution witnesses who are coming forward now, instead of 36 years ago when the murder happened.
For example, one witness, John Griffin, is expected to testify that Reed told him what it felt like to kill a cop. But Peccia said Griffin is serving a prison sentence, and is looking to make a deal to get out.
Peccia also tried to cast doubt on the prosecution's case, by noting the entire file of documents from Trimble's trial in 1972 has disappeared.
The prosecution's first witness was Sackett's widow, Jeanette Sackett-Monteon, who testified through tears how, early on the morning of May 22, 1970, two police officers showed up at her door to tell her the news. She said they didn't have to say a word.
"I knew Jim was gone," she said.
Retired police officer Glen Kothe, Sackett's partner, also testified, telling the jurors that when he and Sackett arrived at the house on the corner of Hague and Victoria Avenues, they knocked on the front door but got no answer.
"I knocked on the back door, and a dog started barking. I leaned over a railing and yelled to Jim that there was a large dog and to watch out," he said. "There was loud bang and a bright flash."
Kothe said he believed the flash was from a gun being fired and that the shot came from a location west of the house and across the street. Then, Kothe said, he heard a scream or loud cry.
"I ran around to the front and found Jim on the ground," he said.
Prosecutors have charged another man, Larry Clark, with helping Reed plan Sackett's killing. Reed and Clark are being tried separately. Clark's trial follows Reed's, which is expected to take three to five weeks.
(The Associated Press contributed to this report)