Interviews from a Boston College oral-history project that became embroiled in a murder investigation have led to the arrest of an alleged former Irish Republican Army leader in Northern Ireland.

Ivor Bell, now 77, was charged with aiding and abetting the murder of Jean McConville, a widowed mother of 10 who was abducted and killed in 1972, allegedly for being an informer for the British Army.

Boston College’s Belfast Project collected interviews with former members of the IRA and other paramilitary groups who were active during the decades-long civil conflict known as the Troubles. The interviews were subpoenaed by law-enforcement authorities and turned over to the police in Northern Ireland last year.

Mr. Bell was allegedly one of those interviewed, but he denied that he had had anything to do with Ms. McConville’s death....