I'm saying right now that this is Shuukan Bunshun, so take this article with a pinch of salt.
AKB48 Kasai Tomomi – Unable to wait until the graduation, the betrayal to her fans.
AKB48 Kasai Tomomi slept over at AKS’s president Mr.Kubota’s house (with evidence photos), Shukan Bunhun reports in upcoming issue of their magazine.
Let us introduce protagonists of this captivating story. The man is Kubota Yasushi, the head of AKB48 group’s management company AKS, great entrepreneur who created this enormous idol group from the ground. The heroine is Kasai Tomomi of AKB48, who has kept high popularity in the fandom. She recently made a headline with her revealing alleged child pornography Gravure photo, but anyway, she announced her graduation after that fuss. She is scheduled to graduate AKB48 on May 3rd and already wrapped up her final handshake session as a member of AKB48.
( long tabloid article under cutCollapse )
tl;dr: Chiyuu was papped at the president of AKS's house. Since he's AKS president, he's close with many AKB members, and often gets into 'scandals' with members. SB have used this as basis of an article to print a bunch or rumours about Chiyuu and present them as fact.
Some of it is well-known, like her often getting sick and cancelling events last minute. Some of it is BS, like that she wasn't pushed at first - she was basically no2 in TK after Yuko at the beginning.