Dog lovers beware - the Bowen Road poisoner is back and has killed at least two animals in the past week. A dog's body was found in a roadside drain in Wan Chai Gap Road, near Bowen Road, on Friday morning. It was the first time the poisoner - who has killed an estimated 200 dogs during his two-decade reign of terror - has struck since December 2010. Another dead dog was found in the same spot yesterday. Pieces of bait, laced with a black powder believed to be a poison, were found in eight locations in the Black's Link area on Saturday, police confirmed, without giving details of the bait used. Officers are investigating whether the cases are linked and have stepped up patrols and put up posters in the Mid-Levels area, which has become notorious for dog deaths since the poisoner first struck in 1989. The Society for the Prevention of Cruelty to Animals warned dog owners to be extremely careful when walking their pets in Mid-Levels. While there is no proof that they have been carried out by the same person, the methods used in the Bowen Road killings have been remarkably similar over the years. Most of the cases have involved dogs eating meat laced with pesticide that causes them to suffer an excruciating death. In 15 to 30 minutes after eating the poison they will salivate and have diarrhoea. Then they start to tremble, shake and have seizures. Full organ failure soon follows. Dog killings elsewhere, including in the New Territories and on Lamma Island, have involved different methods. The SPCA said owners should keep their dogs on a leash and not let them approach anything suspicious. Messages flooded the society's Facebook page, as pet lovers revealed their contempt for the poisoner. 'So unfair. Doggies are punished for their owners' lack of consideration for society,' one said. Another read: 'The dogs haven't done anything wrong. Why take it out on them? If anything is done wrong, it must be by their owners.' A spokesman for the SPCA said anyone who saw anything suspicious should call its 24-hour hotline on 2711 1000. The society is offering a HK$160,000 reward for information leading to the arrest and prosecution of the poisoner, whom it estimates has claimed 200 victims. One theory is that the poisoner has an obsessive dislike of dogs that foul footpaths and may have begun the campaign as revenge. The killings peaked in the late 1990s and early 2000s. Even an appeal on the television programme Police Report in 2008 failed to yield any leads on the poisoner. The most famous victim was Whisky, one of two Norfolk terriers owned by the last governor of Hong Kong, Chris Patten. Whisky was one of the lucky ones, however, making a full recovery after eating poisoned chicken four months before the 1997 handover.