ENCINITAS, Calif. -- Investigators are looking for one of two men who robbed an all-night Encinitas pharmacy, tied up the employee and then led deputies on a high-speed chase before crashing into a tree and running into the dark early Saturday.

One of the suspects is in custody, said San Diego sheriff's Sgt. Thomas Yancey.

The incident started around 2 a.m. Saturday when two armed suspects robbed the CVS Pharmacy at 455 Encinitas Boulevard, he said.

One of the suspects bound three employees, according to Yancey. But a fourth employee's presence was unknown to the robbers, and was able to call 911 and gave sheriff's dispatchers a running description of the suspects' activities, he said.

Deputies set up position outside the store and, about 10 minutes after the original 911 call, one of the suspects walked out the front door and was confronted by a deputy, Yancey said.

That suspect ran back into the store and, moments later, left with a second robber through a rear door and fled in their getaway car, which was parked close by, according to the sergeant.

Deputies chased the car west on Encinitas Boulevard heading west towards Interstate 5, but the suspects vehicle turned north onto Saxony Road to Leucadia Boulevard, Yancey said.

There, the driver tried to turn west towards the freeway but turned too wide and instead drove over the curb and struck a Eucalyptus tree, according to the sergeant.

Both suspects ran, but deputies were able to arrest one of the men. The second suspect remains at large, Yancey said.

The Sheriff's Department has not released the suspects' names or a description of the at-large suspect.