Secret interviews with the Old Bailey car bomber Dolours Price are being handed over to the PSNI today.
The PSNI said two detectives from the serious crime branch have travelled to Boston to take possession of materials authorised by the United States Supreme Court as part of their investigation into the murder of Mrs McConville.
"The officers will return to Northern Ireland to assess the material and continue with their inquiries," a spokesman added.
Price, who died in January, was an unrepentant republican hardliner who became a bitter critic of Sinn Fein when the party endorsed the Good Friday Agreement and encouraged the IRA to give up its weapons.
She clashed with party leader Gerry Adams in recent years over her allegations that he had been her IRA Officer Commanding during the early 1970s.
The 62-year-old consistently claimed that Mr Adams, now a Louth TD, had ordered the kidnap and killing of Mrs McConville in 1972.
Mrs McConville was among up to 20 people – later known as the Disappeared – who were abducted, murdered and secretly buried by republicans during the Troubles.
Mr Adams has always denied being a member of the IRA.
Price said she had made the claims in an interview with researchers working for the American university who aimed to compile an oral history of the Troubles.
The recordings were started in 2001 and were made on the condition that confidentiality would be guaranteed until after the death of the republican and loyalist paramilitaries who took part.
But researchers at Boston College last year lost a Supreme Court challenge in the States when they tried block the release of the tapes after the PSNI launched a high-profile legal challenge to obtain the testimony.
Dolours Price, the former wife of actor Stephen Rea, was convicted and jailed along with her sister Marian for the 1973 attack on London's Old Bailey courts in which one man died and more than 200 people were injured. She spent eight years in jail including months on hunger strike before being released in 1980. She died in January 2013.