The two robberies occurred at a 7-Eleven in Irvine and a Marriott hotel in Santa Ana within a span of 20 minutes from each other.
In each incident, the suspect was wearing a black mask and held the employees at gunpoint.
Surveillance video shows a 7-Eleven clerk being confronted by the suspect with a gun. The suspect ran from the incident without any money after the clerk refused.
Video from the other robbery showed the suspect holding up a hotel employee at gunpoint.
Police believe the suspect could be the same man tied to some robberies earlier this week, which occurred within a short distance from one another, including at two other hotels.