ZAGREB, Dec 11, 2013 (AFP) -Croatian police have launched an investigation after 46 dogs found were found dead in an animal shelter just outside the capital Zagreb, officials said Wednesday."We are all horrified with what we have seen," Brankica Capek, the agriculture ministry's chief veterinarian told state news agency Hina.The remains of the dogs, of various breeds, were discovered at the Astor shelter on Tuesday. They have been transported to a veterinary institute to allow experts to determine the cause of death, Capek said."Prosecutors and police are conducting an investigation and we can not speculate on a cause of death until the autopsy results," she added. The results are expected in the coming days.Local media reported that the dogs were believed to have been poisoned.Activists from the Astor shelter were not immediately available for comment.Luka Oman of the non-governmental group Animal Friends Croatia said he hoped the probe would "determine not only the perpetrators of this criminal act, but also the motives behind it"."Such a case has never happened in Croatia before," Oman said, calling for tougher measures to be introduced against animal cruelty.Under the EU country's criminal code, animal cruelty is punishable by a fine of up to 15,000 kunas (2,000 euros, $2,706) or up to one year imprisonment."For such a horrible case, such punishment is definitely not enough," Oman said.