SDCL § 15-8-18: Restrictions on discharge from contribution obligation by release given by injured party.

A release by the injured person of one joint tort-feasor does not relieve him from liability to make contribution to another joint tort-feasor unless the release is given before the right of the other tort-feasor to secure a money judgment for contribution has accrued, and provides for a reduction, to the extent of the pro rata share of the released tort-feasor, of the injured person's damages recoverable against all the other tort-feasors.