A Montana man once accused of plotting to kidnap David Letterman's son has been arrested on a parole violation.

According to Lewis and Clark County Undersheriff David Rau, Kelly Allen Frank was taken into custody Wednesday near Helena.

Annette Carter, of the Lewis and Clark County Probation and Parole Office, tells the Great Falls Tribune that Frank was arrested for violating the employment and travel conditions of his parole. Carter did not know exactly how Frank had violated his parole.

Frank was paroled in September 2014 after spending nine years at the Montana State Prison for theft.

He was arrested in 2005 and accused of plotting to kidnap Letterman's son and the boy's nanny to extort money.

Frank is being held at the Lewis and Clark Detention Center.