• Itumbi on Monday lashed out at newspaper for linking him to letter.
Activist Boniface Mwangi has said he warned digital strategist Dennis Itumbi about working with politicians.
In a tweet on Wednesday, he said, "I called him (Itumbi) to say that he should be careful while working for politicians. I could tell he was a pawn in a bigger scheme."
Boniface made the statement following Itumbi's arrest.
Itumbi is the secretary digital, innovations and diaspora communications at State House. He is based at Deputy President William Ruto's office at Harambee Annex.
Itumbi was arrested over links to the fake assassination letter against Ruto.
Through his lawyers, Chelanga Kihungi and Associates, Itumbi protested his arrest.
Mwangi recounted Itumbi's arrest in 2012 over claims he hacked the International Criminal Court (ICC) website.
The activist said he warned Itumbi to be careful when working with politicians for favours but he did not listen.
"When President Uhuru was elected in 2013, I met Itumbi after he was appointed digital director at State House. Civil servants believed he was unqualified for the position," Boniface said.
Mwangi advised him to stay strong.
After years of working for State House, Mwangi said Itumbi stopped caring about others and became "the most rapid abuser and creator of hashtags aimed at discrediting anyone he thinks is opposing the President or any of his close politicians."
"Itumbi’s arguments are not based on law, facts or logic, but emotions and hype," he said.
In 2014, Boniface said Itumbi went on national TV to falsely accuse him after years of being his friend.
Mwangi said Itumbi lied that he teargassed Lang'ata Primary School children.
"That was a big lie. Teargas is only imported by the state and civilian possession of it is a crime," he said.
"Dennis Itumbi is a proven liar. He reminds me of Joseph Goebbels, Hitler’s chief of propaganda."