They were dating. Since two weeks. Sully and Brennan are dating.
Ever since Booth and Brennan were seing less of eachother, ever since Brennan always said she had plans with Sully when he asked her about getting lunch together or declined when he wondered about getting stake out. They only saw if there was a case, even then Booth noticed how Brennan started changing, she only wears long sleeves even when it's hot outside sometimes he notices that a flash of hurt passes through her eyes sometimes he thinks she flinches to sudden or loud sound like a door slamming. Even thought she says 'she's fine' Booth doesn't believe her, everytime sully is in a room with her she's unusally quiet even when there alone she's more quiet than usual.
While Booth thought about this he didn't notice Brennan marching into his office
"Booth? Hello?" she asked confused to why he isn't answering, he finally snaps out of it.
"sorry, i was just in my thoughts" he replied
"I don't know what that means" Brennan said matter of factly
"It means that i was thinking" Booth explained " so, is there a reason you're here?" he questioned Brennan
"Yeah we have a ID on our latest victim" she responded giving Booth the file as he opened the file, Brennan spoke up "Matt Davis 21 years lives here in DC, we also found notches on the fith rib probaply from a pocket knife."