Wang was the deputy mayor and police chief in Chongqing, a huge city in south-west China which was run by Mr Bo.
In February this year Wang Lijun fled to the US Consulate in Chengdu, about 300 miles away.
At first Mr Heywood's family were told he'd died from "excess alcohol consumption" and the UK consulate , with family consent, had allowed his body to be cremated immediately.
The US told the UK, and after William Hague had been briefed, the UK asked China to investigate.
The court heard she'd poisoned him. Bo Xilai was suspended from his powerful position and he hasn't been seen in public since March.
Sources have told ITV News that Bo will face criminal charges in connection with the cover-up of the Mr Heywood's murder.
The Bo family had used him as a middle man and he'd become a family friend. Bo's wife was godmother to one of his children.
Now she is the convicted murderer of her godchild's father.
41-year-old Heywood had even helped Bo Gua Gua, the powerful couple's son, get into his former public school, Harrow.
Bo, according to evidence in Wang's trial, knew about his wife's involvement as early as January this year.
When confronted by Wang he hit him and that's when the police chief made his dash to the US Consulate fearing for his life and seeking asylum.
The 15-year sentence is considered relatively lenient for the crimes of "bending the law for selfish ends, defection, abuse of power and bribe taking".
The court indicated that Wang's co-operation, once he'd left the US Consulate with his bid for asylum refused, had been treated as mitigation.
So the former police chief is seen officially as a whistle-blower.
His evidence can now be used against Bo Xilai in a future criminal case.
Bo, once tipped for the top, will now spend the rest of his days locked up, either under house arrest in a secluded villa far from public view or in prison.
The death of Mr Heywood and the political fallout that followed has shocked many in China.
The scandal has revealed that senior Party bosses like Bo Xilai live a luxurious life, with foreigners helping them buy expensive properties overseas and despite Bo's modest official income of around £13,000, his son was sent to expensive private schools in England.
Despite heavy censorship, the details have spread fast thanks to the rise of Chinese social media sites.
Closing the Bo Xilai chapter is now important because China's rulers don't want too many more questions asked about the lifestyles of the leadership.
Putting Bo Xilai on trial, shifts the focus of his case away from an internal party investigation into bribery and money laundering.
In a few weeks time the Communist Party will announce the names of the new leaders who will run this vast, cash rich country for the next decade.
China wants the world to see Bo as a criminal, not a corrupt senior leader.