Martin McGuinness has expressed concern that "state agents" intent on creating problems for Sinn Fein were involved in the two murders that have rocked powersharing at Stormont.
Sinn Fein's Deputy First Minister said he feared elements opposed to the peace process had a hand in the killings.
Mr McGuinness said those elements also wished to create difficulties for DUP leader Peter Robinson, who last week stood aside as First Minister amid the crisis prompted by the murders of former IRA men Jock Davison and Kevin McGuigan.
"The more I consider and the more I think about how all this began - the murders of two people, and our hearts absolutely go out to their families, Jock Davison and Kevin McGuigan - you need to be stupid folks not to be asking the question whose agenda is best served by those murders," he said.
"It certainly wasn't our agenda, it wasn't Sinn Fein's agenda, it wasn't the Sinn Fein peace strategy agenda, and in my opinion it wasn't Peter Robinson's agenda. This is something that has caused huge problems for us within the political institutions."
He added: "So I think serious questions have to be asked about whose agenda was served by those murders, particularly as we all know that the prospect that agents were involved, people who are hostile to the peace process, who are hostile to Sinn Fein's involvement in the political institutions."
He said the murders had "created problems" for Sinn Fein and Mr Robinson.
"The roots of this is two murders and the people who are responsible for those murders are either criminals, agents, dissidents - they are certainly not supporters of ours."