He was portrayed by famous actor Laurence Fishburne who also portrayed Thrax.
Omar is a well-known ruthless crime lord who ruled the streets and worked with Serbian gangsters for business deal which involved fake passports. James and his sister's boyfriend Ben Barber (who is a rookie cop) worked constantly on finding him.
When they are close to solving the case, Ben (who was ordered by James to stay behind in the car) found out that Miggs and Santiago has betrayed James while revealing themselves as double agents working for Omar.
Santiago not only mocks James, but also criticizes him for his unsociable, egocentric personality. As the deal begins, Ben enters pretending to be Omar (since no one has ever actually seen the real Omar). He pulls it off for a moment by shooting one of the goons in the leg after the said goon makes a comment on Ben's height.
Ben takes advantage of the situation to insult James as he is tied up, and also slapping him. The goons want Ben to stab James (after Ben gave a fake threat of doing so) to make it convincing, but he only barely pokes him. He then instead decides to cut James loose, claiming to 'torture him later' and prepares to take him out, but decides instead to continue letting the charade go on, after one of the goons makes a comment that Ben considers disrespect.
That's when the REAL Omar (Laurence FIshburne) comes out, revealing himself to everybody. Omar is impressed Ben shot one of the goons in the charade, but says "when Omar shoots Roberto, Omar SHOOTS Roberto" and coldly shoots the injured goon in the head, execution style, proving the stories of him are correct.
Omar knows of James's pursuit of him, revealing he was watching James this entire time, and he offers to let him into his crew. James refuses and informs Omar and the gangsters that the weapons are nothing but replicas. Before long the situation becomes violent and leads into a shootout (in which Ben uses the skills from the game he and his online friends play, as helpful tips in their survival).
Santiago and Miggs arrive at Angela's apartment and tie her up. As she was playing one of Ben's video games, Ben's fellow players hear the confrontation ensuing between Angela, Miggs and Santiago from Ben's headset. At the hospital after being shot in the leg, Ben receives a call from the fellow player, and tells James that there's something going on at the apartment. After seeing some dirty cops arrive at the hospital, James takes Ben and leaves to go to the apartment, along with Omar's money. James then injures Miggs, before getting into a fight with Santiago. As Santiago is about to shoot James, Angela knocks him out with a frying pan. Ben gets knocked out by Omar in a fight, before Omar takes the bag of money and Angela, and leaves the apartment.
Omar (along with Miggs and Santiago) is finally arrested for his crimes, and is last seen going into an ambulance.
Omar is a notorious crime lord who has never been seen by anyone, not even his own crew, and is considered a ghost because James says "that's his power".
Omar is sadistic, unpredictable and extremely violent. He kills anyone that gets in his way (even his own allies). However, he is also very smart, as he was secretly watching a veteran, violent cop like James Payton without it being known.