Dallas PD says they got the guy who gunned down rapper Mo3 in cold blood, slapped him with a murder charge and turned him over to the feds ... 'cause he's in even more trouble.
Homicide detectives say they tracked down Kewon Dontrell White on Wednesday after getting a tip from a witness about his alleged involvement in Mo3's November 11 killing in Dallas. Cops tell TMZ ... they believe White is the armed man seen on surveillance video running near the murder scene.
It appears White either knew Mo3 or was tailing him -- detectives say they have evidence placing him near the rapper a full day before the shooting, and also on the day of the murder.
As we first reported, sources told us Mo3 knew he was being tailed as he left a female companion's home the morning of November 11. A car chase ensued that ended on the I-35 freeway, and Mo3 was gunned down as he tried to flee on foot.
Cops tell us 22-year-old White is now in federal custody for a charge of prohibited person in possession of a firearm ... in addition to the murder charge in Dallas.
TMZ broke the story ... Mo3 was pronounced dead at a hospital after the shooting in his hometown. An innocent bystander on the freeway was also shot and treated for non-life-threatening injuries.