A known associate of the Bandidos biker gang has pleaded guilty to obstruction of justice in Ontario's worst mass slaying.

The new detail in the case comes after CBC News won a court challenge Friday to disclose key facts involving the discovery of the bodies of eight men linked to the motorcycle gang on April 8, 2006. They were found in abandoned vehicles in a rural area outside Shedden, which is near London.

Eric Niessen, who was visiting the residence of one of the men charged in the deaths, has been sentenced to two years in prison as a result of his guilty plea.

He had initially been charged with first-degree murder. That charge was dropped but he was facing a charge of being an accessory after the fact.

According to an agreed upon statement of fact, Niessen did not witness the deaths and does not know who killed the men.

Court documents say that Niessen and his common-law wife Kerry Morris went to visit Wayne Kellestine, one of the men accused of first-degree murder, on April 8 in Dutton-Dunwich Township.

The documents say that when they arrived, there were only three people there: Kellestine, and Frank Mather of Dutton-Dunwich Township and Brett Gardiner of no fixed address, who are also charged with first-degree murder in the case.

Saw police vehicles

Niessen also noticed a number of marked and unmarked police vehicles surrounding the property, according to the documents. Some time after his arrival, he realized police were there in connection with the discovery of the eight bodies in nearby Southwold Township.

On April 9, Niessen was seen carrying buckets of water from the house to the barn.

"Forensic evidence collected and analyzed from the floor of the barn provides evidence to establish" one or more of the men had been shot there, the court documents state.

Niessen saw Gardiner filling up a pail of water, saw Mather with a pail by the doorway to the barn and saw him take another pail into the barn. But Niessen does not know if anyone washed the surface of the barn floor to destroy evidence, the documents say.

On April 9, Niessen searched the ground of the Kellestine property, looking through the grass, and under the porch of the home, the documents say. These were areas where the men were shot and where shell casings could have been left, according to the documents.

But there is no evidence that Niessen found anything significant, say the documents.

In his guilty plea, Niessen admitted he lied to police and "participated in an alibi" for Kellestine he knew to be false.

Niessen, a Monkton, Ont., native, also admitted that while he was searching in the grass and helping to get water to the barn, he was aware that people at the house were destroying physical evidence and that some of it may have been related to the homicides.

An accessory after the fact charge against Morris has been dismissed.