J.M. Dawson is the Chief of Police of the International Settlement of Shanghai and a minor antagonist.
Dawson is one of the villains in The Blue Lotus. In revenge for Tintin's rebuking of his American friend the businessman Gibbons, Dawson attempts to have Indian prison guards beat up Tintin. Dawson subsequently turns him over to the Japanese who have a price on Tintin's head, calmly dismissing Tintin's protest that he is on neutral ground by pointing out that since Tintin does not have papers allowing him to be in the settlement, Dawson has every right to throw him out.
At the time of The Red Sea Sharks, he sells weapons to both General Alcazar and General Tapioca using the pseudonym Mr. Debrett, and is being patronized by Rastapopulous. He has Tintin and Captain Haddock denied entry to Khemed and plants a bomb on the return plane. His plan ultimately fails.