Police take Zhang Xiaobo in for questioning on Wednesday over the killing of TV reporter Li Xiang in Luoyang, Henan province. Zhang is one of two men suspected of stabbing the journalist to death in a robbery on Sunday. [Photo/provided to China Daily]

ZHENGZHOU - Police have detained two suspects in the hunt for the killer of a TV journalist, whose death many people speculated was linked to his reports on a "gutter oil" scandal.

Zhang Xiaobo, 28, and 24-year-old Li Junzhao were taken into custody at a train station as they attempted to flee Luoyang, Henan province on Tuesday night.

They are accused of stabbing Li Xiang 13 times during a robbery outside his home as he returned from a karaoke session early on Sunday morning.

Netizens and media reports suggested the victim, a 30-year-old reporter for Luoyang TV, may have been murdered by hired killers, as his last micro blog message was about an underground plant making gutter oil, illegally recycled kitchen oil.

However, police officers investigating the case on Wednesday confirmed the case was a "random robbery homicide".

Neither suspect knew the victim, according to a police statement. They came up with the idea while drinking liquor, it said, adding that they had attempted two unsuccessful robberies before attacking Li Xiang.

They are said to have followed him on a motorcycle to a dark lane outside his apartment and threatened him with a single-edged knife. When he refused to hand over his bag, Zhang stabbed him, police said. Li Xiang died from a loss of blood.

The police offered a reward of 20,000 yuan ($3,100) for information about the incident, which prompted the two suspects - both residents of Luoyang - to try and flee on Tuesday night.

A knife was found abandoned in a public toilet in the town where they live, while police say they also recovered a camera and a wallet believed to belong to Li Xiang.

Zhang served a prison term from 2001 to 2007 for an earlier robbery, the report said.

The case is still under investigation.