Pentaquarks and strange tetraquark mesons

We consider the interplay of the pentaquark states and strange tetraquark states in the decay $\Lambda^0_b\to K^-J/\psi p$. Possible existence of ($cs\bar c\bar u$)-states is taken up and their manifestation in the $K^-J/\psi $-channel is discussed. It is emphasised that these exotic mesons can imitate broad bumps in the in the $pJ/\psi $-channel.