National Drug Control Agency Chief Rolando Rosado says the killing of army Col. Cesar Ubri was meant as a warning from drug traffickers, but he vows to catch the assailants.

Ubri had worked for the agency for 18 years and was Rosado's personal assistant. Gunmen approached him as he was getting out of his car late Sunday in the upper middle class Las Praderas neighborhood and opened fire, hitting him at least five times. A woman who was with him was not injured.

Hundreds of police officers spread across the city Monday in search of the attackers.