(CNN)In the vital transport corridors of the troubled Gulf of Aden, an old but dangerous adversary has returned to the seas — pirates.
But they may not be acting alone.
Four years since piracy attacks reached their peak, CNN sources have found threats on Somali waters are broader than ever.
CNN has learned that the United Nations and the United States are investigating at least two pirate kingpins for providing material support to terror groups.
That material support includes helping factions of the two terror groups, al Qaeda linked al-Shabaab and Somalia’s ISIS faction, who ironically despise each other, smuggle weapons and perhaps even people across the Gulf of Aden.
One of them is Mohamed Garfanje, the kingpin of the Hobyo-Haradhere Piracy Network, which thrived in the tiny fishing village of Haradhere — often considered the birthplace of modern Somali piracy.
Garfanje is also one of the main suspects wanted for the kidnapping of American-German journalist Michael Scott Moore in 2012.
Moore tells CNN he met Garfanje during the harrowing two years and a half he spent as an hostage.
According to three sources CNN has spoken to, Garfanje is believed to have helped al-Shabaab smuggle weapons and ammunition into Somalia.
He is also still carrying out pirate attacks, according to leading piracy watchdog organization, Oceans Beyond Piracy.
“Garfanje should be in jail,” Moore said. “If it’s true that he and Bakeyle (another pirate) are out catching ships again, then they should be rounded up by authorities and prosecuted.”
Another pirate kingpin, whom CNN is not naming, is believed to have been smuggling arms and people to ISIS’ small but worrisome faction in Somalia, based in Qandala, in the semi-autonomous region of Puntland, according to UN and US sources.
UN sources say he has assisted ISIS with logistics and has a relationship with Abdulkadir Mumin, the leader of ISIS in Somalia.
Oceans Beyond Piracy researchers believe he is behind some of the recent piracy attacks in the Gulf of Aden.