The video shows the man vaping before officers say he stabbed 22-year-old Treeanna Nichols of Pasadena to death inside a hotel room at the Quality Inn in the 6600 block of Westminster Boulevard.
Authorities responded to the hotel the night of Feb. 5 and found Nichols unresponsive in one of the rooms.
Detectives are looking for the suspect and his vehicle, a late model four-door dark sedan.
The motive and how the suspect knew Nichols is still under investigation.
Anyone with information about the case is asked to call the Westminster police detectives at (714) 898-3315 ext 4572.