A Ghanaian politician who promised to pay anyone who attacked an undercover reporter has been questioned as part of the investigation into his death, police have announced.Ahmed Hussein-Suale, who worked on a high-profile investigation into corruption in African football, was gunned down as he returned to his home in Accra last week.The killing sent shockwaves through Ghana, which prides itself on being a stable democracy in an often turbulent region, and where there is a high level of media freedom.Police spokesperson David Eklu said in a statement on Monday that detectives had begun a "extensive and rigorous" investigation into the journalist's death."A team of detectives and other experts have interrogated Kennedy Agyapong, member of parliament for Assin Central, and a statement (was) taken from him," he added.Agyapong's name was mentioned as part of the corruption expose. He later went on television, showed Hussein-Suale's photograph and said he would pay anyone who attacked him.He has since denied claims that he had "engineered the killing" and said he had never been offended by Hussein-Suale. But he remained critical of the reporter and Anas Aremeyaw Anas, his boss at the production company behind the investigation."The evil they have been doing will follow them," said Agyapong, who is a member of President Nana Akufo-Addo's New Patriotic Party.Anas, who hides his face in public under a variety of hats and disguises, has also been threatened.Police have offered a 15 000-cedi ($3 000) reward for any information leading to the arrest and conviction of those responsible for Hussein-Suale's death.The investigation led to the resignation of the head of the Ghana Football Association and sanctions against dozens of referees, assistant referees and other officials.Anas has previously lifted the lid on corruption in the judiciary.Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.