Conn. Gen. Stat. § 5-179: Services paid for by federal grant.

The time during which any state employee performed services, the direction of which remained in the state agency to which such employee was attached although his compensation was paid directly by federal grant, shall be considered a part of his state service for retirement purposes, provided his retirement contributions have been continuous since September 1, 1939, or, if not continuous, have been made with interest thereon at the rate of five per cent per year.