Mahama in a Facebook post said "We woke up to the sad news of the killing of investigative journalist, Ahmed Hussein-Suale. My condolences to his family and colleagues at Tiger Eye PI.
"For a democracy like Ghana, which is a model for our continent, things like this should not happen. There’s been a spate of killings in our country lately, and we urge government and the security agencies to be up and doing and bring the perpetrators of these dastardly acts to book."
Ahmed Hussein-Suale was killed at Madina in Accra on Wednesday evening while driving home. He was shot twice in the chest and once in his neck.
Anas Aremeyaw took to Twitter to eulogise his colleague and noted that the team would not be deterred in the fight against corruption.
He wrote "Sad news, but we shall not be silenced. Rest in peace, Ahmed."
However, President Nana Addo Dankwa Akufo-Addo also asked the Police to immediately work to arrest the killers.
He said he expects the police "to bring to book as soon as possible, the perpetrators of this heinous crime."
Ahmed Hussein-Suale was shot dead on Wednesday
He said "I've learnt with sadness of the killing of Ahmed Hussein-Suale, an associate of investigative journalist, Anas Aremeyaw Anas. I condemn the act unreservedly, and extend my condolences to his family. I expect the police to bring to book, as soon as possible, the perpetrators of this heinous crime. Once again, my heartfelt condolences."