BLANTYRE, Malawi (AP) Police in Malawi arrested a former justice minister on suspicion of involvement in the Sept. 13 shooting of the country's budget director, a corruption fighter who was seriously injured, police said Friday.

The detention of Ralph Kasambara, who became justice minister last year and was replaced in a Cabinet reshuffle last month, comes amid a campaign by President Joyce Banda to root out graft at the highest levels of government in one of Africa's poorest countries.

Kasambara was detained at his house on Thursday night in Lilongwe, the capital, police spokesman Kelvin Maigwa said. Another suspect, businessman Pika Manondo, turned himself over to police in a border district on Thursday after driving into Malawi from neighboring Tanzania. The two will likely be charged in court after investigators question them, Maigwa said. Three other suspects, including Manondo's brother and a former soldier, are already in custody.

"We have gathered evidence which suggests that Mr. Kasambara was involved in the shooting," Maigwa said. He provided no further details.

The 37-year-old budget director, Paul Mphwiyo, was shot as he drove into his residence in a suburb of Lilongwe. Banda said the shooting was linked to his campaign against corruption in state institutions.

A number of former government officials currently face fraud and corruption charges. Banda has been trying to stem official corruption and wasteful spending since coming to power in April 2012 following the death of Bingu wa Mutharika, the former president. She took a pay cut and sold off a presidential jet that had been purchased by her predecessor as part of the new government's austerity measures.