We construct the Rarita-Schwinger basis vectors, U µ , spanning the direct product space, U µ := A µ ⊗ u M , of a massless four-vector, A µ , with massless Majorana spinors, u M , together with the associated field-strength tensor, T µν := p µ U ν − p ν U µ . The T µν space is reducible and contains one massless subspace of a pure spin-3/2 ∈ (3/2, 0) ⊕ (0, 3/2). We show how to single out the latter in a unique way by acting on T µν with an earlier derived momentum independent projector, P (3/2,0) , properly constructed from one of the Casimir operators of the algebra so(1, 3) of the homogeneous Lorentz group. In this way it becomes possible to describe the irreducible massless (3/2, 0) ⊕ (0, 3/2) carrier space by means of the anti-symmetric-tensor of second rank with Majorana spinor components, defined as w (3/2,0) µν := P (3/2,0) µν γδ T γδ . The conclusion is that the (3/2, 0) ⊕ (0, 3/2) bi-vector spinor field can play the same role with respect to a U µ gauge field as the bi-vector, (1, 0) ⊕ (0, 1), associated with the electromagnetic field-strength tensor, F µν , plays for the Maxwell gauge field, A µ . Correspondingly, we find the free electromagnetic field equation, p µ F µν = 0, is paralleled by the free massless Rarita-Schwinger field equation, p µ w (3/2,0) µν = 0, supplemented by the additional condition, γ µ γ ν w (3/2,0) µν = 0, a constraint that invokes the Majorana sector.