The wife of a Chinese former top politician at the heart of a scandal that has rocked the ruling Communist Party has admitted murdering a British businessman and blamed her actions on a \"mental breakdown\", state media reported Friday. Xinhua news agency said Gu Kailai told her murder trial that she suffered the breakdown after \"learning that my son was in jeopardy\", in a report released the day four Chinese police officers reportedly confessed to covering up the killing of Neil Heywood. Gu, who is accused of poisoning the 41-year-old businessman with cyanide in a hotel room last November when he was drunk, said she would \"accept and calmly face any sentence\" handed down by the court, Xinhua said. She also said she would \"shoulder responsibility\" for losses to her party and country, it added. In a statement to the court at the end of the one-day hearing on Thursday, the wife of disgraced former Chongqing Party secretary Bo Xilai said she accepted all the facts in the indictment, Xinhua added. She told the court the case had been \"like a huge stone weighing on me for more than half a year\". \"During those days last November, I suffered a mental breakdown after learning that my son was in jeopardy,\" she said, referring to Bo Guagua who is believed to have had a dispute with Heywood over money. \"The tragedy which was created by me was not only extended to Neil, but also to several families. \"The case has produced great losses to the Party and the country, for which I ought to shoulder the responsibility, and I will never feel at ease. I am grateful to the humanitarian care shown to me by those who handled the case. \"I solemnly tell the court that in order to maintain the dignity of the law, I will accept and calmly face any sentence and I also expect a fair and just court decision.\" In her testimony Gu reportedly said: \"It was in about 2005 when my son was studying in Britain that Neil Heywood wrote us a letter of self-introduction, showing his intent to get to know us.\" She said that her son and Heywood got into a \"dispute\" over a \"land project\" that \"never got started\". The dispute then escalated. \"To me, that was more than a threat. It was real action that was taking place. I must fight to my death to stop the craziness of Neil Heywood,\" Xinhua reported Gu as saying. Xinhau said that a panel asked to assess Gu\'s mental state had concluded that she had been treated for \"chronic insomnia, anxiety and depression, and paranoia in the past\". It had found that she used to take antidepressants and had \"developed a certain degree of physical and psychological dependence on sedative hypnotic drugs, which resulted in mental disorders\", Xinhua added. However, the experts said Gu \"had a clear goal and a practical motive in committing the alleged crime\" and \"should be identified as having the capacity to accept full criminal responsibility\". Xinhua added that Zhang Xiaojun, Gu\'s co-defendant, had confessed his involvement in the murder and wanted to say \"sorry\" to the victim\'s relatives. Gu\'s government-appointed lawyer did not challenge the charge that she poisoned Heywood after going to drink with him in the hotel room where he was found dead, court official Tang Yigan told journalists after Thursday\'s hearing. The verdict will be delivered at a later date -- possibly days or weeks away. On Friday four policemen admitted to covering up the killing to protect Gu, an official said. All four were senior police officials in Chongqing, the southwestern megacity that Bo ran until he was sacked in March, and where Heywood\'s body was discovered. Tang, the official with the Hefei Intermediate Court in eastern China, told reporters their one-day trial had ended late Friday and that a verdict would be issued at a later date. \"The defendants admitted that the charge of bending the law for selfish ends was basically correct,\" he said of the four, named as Guo Weiguo, Li Yang, Wang Pengfei and Wang Zhi. The court heard how the officers covered up Gu\'s involvement in Heywood\'s death by \"forging interview scripts and hiding evidence,\" agreeing to say he died of excessive alcohol consumption. It is not clear whether Bo, who was one of China\'s most senior leaders until his downfall earlier this year, knew about the alleged cover-up, although the hearing was being closely watched for any hints on his likely fate. Experts say the process has been carefully stage-managed to minimise embarrassment to China\'s communist rulers after the scandal, which ended her husband\'s career and exposed divisions in the party. The party is keen to resolve the crisis before a 10-yearly handover of power later this year, when seven of its most senior leaders will stand down from their positions and hand over to a new generation, they say. \"It is quite clear that the authorities have reached an agreement over Bo Xilai,\" said Joseph Cheng, professor of political science at the City University of Hong Kong. \"(Gu\'s) trial went so smoothly and according to the script... there was no mention of corruption and Bo Xilai\'s name wasn\'t mentioned.\" Bo was sacked from the powerful 25-member Communist Party Politburo in April and placed under investigation for violating party discipline -- usually code for corruption. Nothing has been heard from him since. Gu\'s trial drew comparisons with that of Chinese leader Mao Zedong\'s widow Jiang Qing, who along with the three other members of the \"Gang of Four\" was convicted for fomenting the tumultuous Cultural Revolution. While murder carries the death penalty in China, legal experts say Gu is likely to be spared execution and will instead face a long jail term.