China's ruling Communist Party took a big step towards sealing the fate of fallen politician Bo Xilai, when a court jailed his former police chief for 15 years over charges that indicated Bo tried to derail a murder inquiry.

The court in Chengdu in south-west China handed down the sentence against Wang Lijun after finding him guilty on four charges, including seeking to cover up the November 2011 murder of British businessman, Neil Heywood, by Bo's wife, Gu Kailai.

The verdict ended the career of one of China's most controversial police officers and moved the party closer to a formal decision on dealing with Bo, whose downfall has affected a leadership handover due at a party congress as early as next month.

Wang could have received life imprisonment, or even a death sentence.

The relatively mild sentence added weight to predictions that the party will move to jail Bo too, said He Weifang, a law professor who has followed the case.

"The legal net around Bo Xilai has been slowly tightening," said He. "He'll face a criminal trial."

Experts have offered divided views over whether the party will put Bo before a criminal court or spare him and the leadership that disgrace by simply meting out lighter disciplinary punishment within the party. Some still see that latter course as more likely.