HOULTON  — A 64-year-old man charged with helping conceal evidence in a triple slaying in northern Maine is back in jail for allegedly selling oxycodone to his 24-year-old grandson.

Robert Strout of Orient was being held in the Aroostook County Jail in Houlton today on a charge of aggravated furnishing of oxycodone.

Strout was charged last year with hindering apprehension and arson for helping Thayne Ormsby after Ormsby allegedly fatally stabbed Jeffrey Ryan, Ryan’s 10-year-old son and neighbor Jason Dehahn at Ryan’s home in the small town of Amity in June 2010. Strout and Ormsby, who is 21, are now being held in the same jail.

Drug agents arrested Strout on Thursday after he allegedly gave 170 tablets of the pain killer to his grandson Craig Strout-Desmond, and 24-year-old Brianna Bonness, both of Ellsworth, according to the Maine Drug Enforcement Agency.

Agents followed Strout-Desmond and Bonness when they drove from Ellsworth to Orient on Wednesday to pick up the drugs. They were arrested that night upon their return to Ellsworth, the MDEA. Strout-Desmond was charged with aggravated furnishing of oxycodone, and Bonness was charged with drug possession and violation of conditions of release in connection with a previous arrest for attempted burglary.

Strout told police last year that he helped Ormsby after the killings because he feared for his life. He is accused of driving Ormsby to a rural road where Ormsby set fire to Ryan’s truck, which he allegedly stole after the killings. Strout said he later drove Ormsby to Strout’s daughter’s house in New Hampshire and dropped him off.

At the time of the killings, Ormsby was staying with Strout and his wife.