Abstract In an experiment with the CERN 2 metre bubble chamber, the reaction K +d→K + π + π −d has been studied at an incident K + momentum of 4.6 GeV/c. The cross section is 250±30 μb. A strong K ∗ (892) signal is seen and also a broad enhancement in the Q region ( M(K ππ) < 1.5 GeV) with no evidence for narrow resonances in this mass interval. The production and decay properties of these objects are studied, and comparisons made with similar reactions on protons. The properties of the angular distributions of the Q decay are very similar to those found in the related reaction on a proton target. The spin-parity of the Q system is found to be predominantly 1 + although 2 − cannot be excluded. The dπ mass distributions show an enhancement for mass values ∼2.2 GeV; however the marked asymmetry in the corresponding decay angular distribution argues against a resonance interpretation of this effect.