  We analyze the invariant mass spectrum of Lambda-Lambda in $^{12}C(K^-,K^+
Lambda Lambda)$ reaction at P(K^+)=1.65 GeV/c by using a combined framework of
IntraNuclear Cascade (INC) model and the correlation function technique. The
observed enhancement at low-invariant masses can be well reproduced with
attractive Lambda-Lambda interactions with the scattering length either in the
range a = -6 \sim -4 fm (no bound state) or a = 7 \sim 12 fm (with bound
state). We also discuss Lambda-Lambda correlation functions in central
relativistic heavy-ion collisions as a possible way to eliminate this discrete
ambiguity.
