Warren Sapp -- Suspect In Domestic Violence Investigation

More trouble for Warren Sapp ... the NFL Hall of Famer has been named a suspect in a domestic violence investigation in Las Vegas ... TMZ Sports has learned.

Law enforcement sources tell us ... a report has been filed against Sapp in which the 42-year-old is accused of getting into a physical altercation with a woman in a casino on April 28th.

We're told cops met with the alleged victim at a different location after the incident and took a report ... though Sapp was not present at that time. Law enforcement sources tell us the woman appeared to have suffered minor injuries.

Our sources tell us Sapp has NOT been arrested or charged with a crime at this point ... though cops are still investigating.

It's just the latest legal problem for Sapp ... who was arrested for soliciting and assaulting two prostitutes in Arizona back in February.

We reached out to Sapp for comment ... so far, no word back.