A text message sent to Chris Brown from another woman may have ignited the explosive argument between the “Run It” singer and girlfriend Rihanna, according to TMZ.

A law-enforcement source who spoke with TMZ said the message asked Brown about “hooking up later.” There were no further details, however, regarding the text or the identity of the person who sent the message. TMZ is also citing an alleged reference in the police report to an argument over a rapper, but that has yet to be confirmed.

Neither party has spoken publicly since reports surfaced about an alleged domestic-violence incident on Saturday. Brown turned himself in to police and was later released after posting $50,000 bail. The singer was charged with making criminal threats, and police are still investigating the matter before turning it over to the district attorney’s office.

Rihanna’s injuries aren’t fully known yet. The Def Jam artist was taken to a hospital, and reports have varied regarding the extent of what happened to her — from large contusions on her face to a bloody nose. Her grandmother told a newspaper in the singer’s native Barbados that Rihanna is “fine.”

According to E!, though, Rihanna reportedly told police Brown choked her and left her unconscious following their altercation, where she allegedly threw the keys of Brown’s rented car out the window, sending him into “a rage.” Police then drove Rihanna to the hospital immediately rather than waiting for an ambulance after noticing her eye was black and swollen. E! is also reporting that Rihanna told police that Brown threatened to kill her.

Both artists backed out of their scheduled Grammy appearance on Sunday night and have canceled a number of upcoming appearances, including a concert overseas for Rihanna and a number of events Brown was set to appear at during NBA All-Star Weekend.

Brown’s Doublemint gum endorsement deal has been suspended, and a number of his songs and past TV appearances have also been removed from airing on radio and TV.