Investigated a collection of suspicious accounts and found last 30 days transactions between them as follows:

Suspicious Accounts

Group Number	Account Names	Suspicious Type
Suspicious #1	@robert31, @steem-ripon	Transactions (Confirmed)
Suspicious #2	@nomita, @sizuka	Transactions (Confirmed)
Suspicious #3	@perry1, @max1994, @rik432, @ratul8940, @rahul72	Transactions (Confirmed)
Suspicious #4	@smileplease, @saqqu, @letssmile	Transactions (Confirmed)
Suspicious #5	@serkagan, @magnata	Transactions (Under Investigation)
Suspicious #6	@ritue, @pariza, @suchi, @maicle	Transactions (Confirmed)
Suspicious #7	@beforandafter, @askmee, @scoopian	Transactions (Under Investigation)

@serkagan & @magnata claimed they are husband & wife. Therefore, closely watching to remove the suspicious notification.