JINAN, China -- In the weeks before Bo Xilai, the fallen Communist Party star, went on trial here on corruption-related charges, senior officials from the powerful party investigation agency told him about two officials who had been tried earlier on somewhat similar charges, Mr. Bo said in court.
One, a former vice governor of Anhui Province, fought back and was executed in 2004 for taking bribes and stealing $1.6 million. The other, a former railway minister, was more compliant; he received a suspended death sentence -- essentially life in prison -- in July, mainly for taking $10.6 million in bribes.
The senior officials' point, Mr. Bo told the court here in a 10-minute speech on Friday, was that the party could mete out any punishment it chose, and that Mr. Bo's fate rested on whether he chose to cooperate during his own trial on charges of bribe taking, embezzlement and abuse of power, according to two people briefed on the proceedings.
Mr. Bo's speech and some other instances in which he railed against threats and hardships during his 17 months in captivity have not appeared in the torrent of court transcripts released publicly during the trial, China's most closely watched in three decades, which ended on Monday. Instead, those transcripts have shown Mr. Bo cross-examining witnesses, ridiculing the testimony of his wife and former colleagues, and seemingly free to play his part as defendant however he chooses.
On Monday, Mr. Bo used the platform of his closing argument to lay bare the secret love triangle involving the prosecution's two star witnesses -- his wife and a former police chief -- that he asserted had ultimately ended his vaunted career.
The trial remains political stagecraft, fashioned around Mr. Bo's combative character, analysts say, despite the fact that the party, in an unexpected show of relative transparency, has allowed millions of Chinese citizens to witness much of Mr. Bo's performance through a running court microblog.
The spectacle, they say, is an effort by the party to convince his elite party allies and ordinary supporters that Mr. Bo, a populist politician and the son of a revolutionary leader, had his say in court, and that the long prison sentence he is expected to get is based on evidence of crimes committed, not political payback. State news media have highlighted daily the evidence presented against Mr. Bo, while officials have limited his airtime in court and in the transcripts to help maintain control.
"The authorities hope to separate the Bo Xilai case from politics," said Chen Jieren, a legal commentator. "They want people to think this was only an anticorruption struggle, not a political and ideological struggle."
While the microblog gambit may have won Mr. Bo additional sympathy and exposed cracks in the prosecution, its show of legal parrying between the defendant and his accusers also lent considerable credibility to the political theater. Perhaps most important for the party, what has most captivated ordinary Chinese -- thanks to headlines in major state media outlets -- is a mountain of testimony that depicts Mr. Bo as the archetypal corrupt official, with a spoiled son and a wife who murdered a British businessman. (She was convicted in August 2012.)
In his closing argument on Monday, Mr. Bo unveiled more explosive elements surrounding his family, and essentially argued that the saga came down to crimes of passion. He said Wang Lijun, the former police chief of Chongqing, which Mr. Bo governed until his downfall in March 2012, had a final falling out with Mr. Bo and fled to a nearby American consulate in large part because of tensions that boiled over from his secret affair with Mr. Bo's wife, Gu Kailai. Mr. Wang had told Ms. Gu that he was in love with her, and that outraged Mr. Bo, he said. His wife and the police chief had been close for years, he said, ever since Mr. Wang came to Chongqing to investigate Ms. Gu's suspicions that she had been poisoned.
"Because he and Gu Kailai were stuck together as if by glue, Gu Kailai took him at his word, and Wang Lijun infiltrated my household because of his association with Gu Kailai," Mr. Bo said Monday. "So now such a serious thing has occurred."
He added: "The two had an extremely special relationship, and I was so sick of it."
Mr. Bo said Mr. Wang harbored an enduring "secret love" for Ms. Gu, and that "his emotions were twisted; he could not free himself." Mr. Wang expressed his feelings in one or more letters to Ms. Gu, Mr. Bo said. One day, Mr. Wang told her of his love and slapped himself eight times in front of her.
According to Mr. Bo, Ms. Gu said: "You're abnormal."
"I used to be abnormal, but now I'm normal," Mr. Wang said, according to Mr. Bo.
Then Mr. Bo suddenly walked into the room, he said, and took the letter or letters away. "He knew my character," Mr. Bo said. "He harmed my family. He harmed my basic feelings. That's the true reason for his defection."
The sequence of events was not clear, but Ms. Gu, according to Mr. Bo, at one point entered a room of Mr. Wang's in Chongqing and stuck 60 or 70 notes on the walls that warned Mr. Wang to be careful. At another point, Ms. Gu brought Mr. Wang's shoes to the Bo family home, and Mr. Bo asked a close aide to take them away, he said.
"This has nothing to do with hatred," Mr. Bo said in his closing argument. "This is a farce that arose from the two of them being glued together."
Like other testimony released to the public throughout the trial, Mr. Bo's speech avoided any mention of party politics, including machinations by other senior officials at the time that involved him and Mr. Wang. The speech appeared to confirm earlier assertions from people close to the case that Mr. Wang and Ms. Gu had had an affair of some sort.
Chinese news portals devoted top headlines on Monday to Mr. Bo's accusation. His closing argument was perhaps the most colorful element in a five-day trial that brimmed with high drama.
Evidence at the trial has also shown that Ms. Gu and their son, Bo Guagua, regularly took favors from a tycoon friend, Xu Ming, including a $3.2 million villa on the French Riviera; a $131,000, six-person vacation to Africa in 2011 that included the use of a private jet; and a $12,000 Segway for the son, who also traveled to Paris, Venice, Argentina, Cuba and, for the 2006 World Cup, Germany. "It was convenient to call Xu Ming," Ms. Gu testified. "He used to pay for things."
Mr. Bo has not denied that those two had a cozy relationship -- he only disavowed knowledge of gifts given -- and the portrait the testimony paints of his family is likely to condemn him in the eyes of many Chinese citizens who abhor the official corruption so rampant in China. It could also be enough to convince ordinary people and leftist intellectuals, who praised Mr. Bo for pushing neo-socialist economic policies and an anticorruption campaign when he was party chief of Chongqing, that he is a hypocrite.
The trial also benefits party leaders by sending a warning to another audience: corrupt party officials. The new party leader, Xi Jinping, is directing a campaign to rein in their lavish living arrangements and bring "tigers and flies" to heel for corruption. The state media have trumpeted Mr. Bo as the biggest tiger caged so far.
Other salacious details of decadence and conflict in the Bo family emerged over the weekend. Mr. Bo testified Saturday that he himself had had an affair that drove his wife and son to Britain. On Sunday, he quibbled over testimony from Mr. Wang, who had said that Mr. Bo punched him, bloodying his face, after he confronted him with suspicions that Ms. Gu had murdered the Briton, Neil Heywood. Mr. Bo insisted he had only slapped Mr. Wang: "I've never trained in boxing," he said, "and I don't have that kind of force."
In another awkward moment, Mr. Bo insisted Saturday that he had not intended to embezzle $820,000 from a state construction project in the city of Dalian, where he had been mayor, and disputed testimony from a planning official that he had told his wife over a cellphone to take the money. "All those who know me well know that I always tell them to turn off their cellphone first when talking with me," he said. "I'm quite a cautious person."
Discussing such matters over cellphones, he added, "doesn't fit in with the behavior of even the most incompetent corrupt criminal."
That kind of testimony has contributed to a less than flattering portrayal of Mr. Bo on the censored court microblog, which had 570,000 followers by Monday.
Online transcripts show him speaking up against his accusers, but only within limits dictated by the party. "He's avoided incriminating other leaders or accusing them of the same crimes, and we know he could do that," said one former corruption investigator. "But he knows not to cross that line."
One clear indication the party's strategy seems to be succeeding is that according to a family associate, Mr. Bo's most loyal supporters -- relatives who are watching the trial firsthand -- seem appeased simply because he has been allowed to defend himself in court.
"The family is relatively satisfied," the associate said, "because he has been given ample opportunity to speak."
Chen Ping, a Hong Kong publisher who knows party leaders, noted that officials were exposing only narrow crimes by Mr. Bo, not the wider abuses liberals accuse him of encouraging during the "strike black" anticorruption campaign in Chongqing. "The party wasn't willing to try Bo Xilai on the charges that he should have faced -- trampling on human rights, trampling on rule of law." he said. "That's because those mistakes are also the party's mistakes."
Still, some liberal voices have approved of the trial's transparency and procedure. Caixin, among China's more independent media outlets, published a commentary on Sunday by Xiao Han, a legal scholar, saying that officials deserved credit for steps toward openness, including allowing the transcripts to show Mr. Bo's insistence on retracting confessions he said were made under mental strain.
He Bing, a law professor, said in an interview that it appeared "the defendant enjoys full rights to defend himself, but whether the trial is fair or not ultimately depends on the verdict."
A verdict is expected in early September.
Chris Buckley contributed reporting from Hong Kong, and Patrick Zuo contributed research.
This article originally appeared in The New York Times.