Questions & Mysteries When did Sengoku find out Ace was Roger's son?

[Dettles]

Obviously Garp always knew, but most of the Marines didn't find out Ace's lineage until Marineford. But when did Sengoku find out? And how did he find out? Did Garp tell him? Or did the Cipher Pol manage to trace him back to his "Birth Island"?

 

[Yoho]

Garp probably told him while drunk on beer and rice crackers

 

[trav]

Blackbeard heard it on WBs ship and snitched.
Ace was BBs entry card to becoming a warlord. More likely to get what he wanted when he delivers not just WBs, but Rogers son.

 

[mly90]

BB was the bigger threat this clown instead went all in against innocent kid just because he carried Roger blood. I wonder how he feels now laying the foundation for BB rise to power

 

[Jesse Pinkman]

I think it’s Garp .

 

[soupongo]

It's never been explained in the manga actually, Sengoku says cipher pol figured it out,but how? Who knows

 

[U c 4 up da idly]

He found out when Ace became a notorious pirate