Yella Beezy is in police custody in Texas, where he's been arrested and hit with a capital murder charge in the death of rapper Mo3 ... TMZ has learned.

The rapper was busted in the Dallas area on Thursday, where he's currently in jail.

According to court documents obtained by TMZ ... Yella is accused of intentionally and knowingly causing the death of Melvin Noble AKA Mo3 on November 11, 2020.

The charging documents accuse Yella of employing a man named Kewon White to murder Mo3 on a Texas interstate by using a firearm.

We reached out to Yella Beezy's lawyer for comment ... so far, no word back.

Story developing ...