  In a paper by Maartens, Lesame and Ellis (Class. Quant. Grav. 15, 1005) it
was shown that irrotational dust solutions with vanishing electric part of the
Weyl tensor are subject to severe integrability conditions and it was
conjectured that the only such solutions are FLRW spacetimes. In their analysis
the possibility of a cosmological constant Lambda was omitted. The conjecture
is proved, irrespective as to whether Lambda is zero or not, and qualitative
differences with the case of vanishing magnetic Weyl curvature are pointed out.
