A parolee told a judge Thursday that he helped conceal evidence against Kevin Harper despite knowing Harper was the prime suspect in a West Valley triple homicide.

Tennance V. Buckingham, 50, pleaded guilty to two felony charges in the long-running Goggin murder case: first-degree rendering of criminal assistance and first-degree trafficking in stolen property.

In exchange for his plea, prosecutors agreed to recommend an eight-month jail sentence. With his criminal history, he would have faced six to eight years in prison under state guidelines.

A sentencing date was delayed until Sept. 26. Until then, Buckingham remains out of custody.

Why prosecutors would agree to such a lenient deal was not explicitly explained in court. However, Buckingham’s court-appointed attorney told the court several times the deal was tied to a “cooperation agreement.”

After his plea, TV news reporters pursued Buckingham and his attorney, Jim Egan, into the corridor outside the courtroom, causing an irritated Egan to send his client back into the courtroom to hide.

Chief Criminal Deputy Prosecutor Ken Ramm, meanwhile, also declined to discuss the plea, particularly questions about the cooperation agreement.

Buckingham was one of four people who once faced charges in the February 2011 bludgeoning deaths of Bill Goggin, owner of a Yakima civil engineering firm, his wife, Pauline, and his mother, Bettye.

Their bodies were found in the family’s home in the gated Falcon Ridge development, west of Yakima. Authorities believe they were killed during a burglary.

Per his plea deal, Buckingham admitted that he helped fence a laptop computer that was stolen from the Goggin home and concealed evidence he believed would implicate Harper. The nature of that evidence was not explained in court.

Harper, 31, was considered the prime suspect and faced three aggravated first-degree murder charges until prosecutors were forced to cut a deal with him after a series of missteps by investigators and prosecutors that threatened to derail the case.

Harper subsequently pleaded guilty to two relatively minor charges — first-degree unlawful possession of a firearm and second-degree possession of stolen property — related to the theft of a Western-style, .22-caliber pistol from the Goggin home.

In exchange for his plea, prosecutors agreed to recommend a prison sentence of just over seven years. They also dismissed accessory charges against his wife, Crystal Gray-West.

Under the plea deal, prosecutors said they would drop murder charges when he is sentenced, which has not yet happened.

And last month, the case was turned on its head when prosecutors accused Harper of violating the terms of a “confidential agreement” behind the plea agreement. That “confidential agreement,” along with the one in Buckingham’s case, has not been made public.

After prosecutors asked the court to hold a closed-door hearing for the purpose of nullifying the plea deal, trial Judge Ruth Reukauf instead scheduled a hearing June 13 to hash out the merits of the request.

Accessory charges against a fourth defendant, Tracy Culton, were dismissed in February after prosecutors said further investigation found insufficient evidence to proceed against her.

• Chris Bristol can be reached at 509-577-7748 or cbristol@yakimaherald.com. Follow him on Twitter at twitter.com/ChrisJBristol.