Alexandria police arrested a second suspect yesterday in th robbery of the Red Lobster Inn restaurant Sunday night in which three restaurant employees were wounded with shot-gun blasts.

Police said Roger Allen Turner, 23, was arrested before dawn at his home in Manassas and charged with armed robbery of the restaurant at 555 S. Van Dorn St. On Monday night police charged Charles P. Sanders Jr., 26, with armed robbery in connection with the incident. Sanders, who lives at 4868 Kenmore Ave., Alexandria, was arrested at the restaurant, where he is a cook. Both men were held at the Alexandria jailed last night in lieu of $50,000 bond each.

In another developemnt, police reported yesterday that skin divers have recovered from the Potomac River near Memorial Bridge the barrel of the shotgun believed to have been used in the holdup.

After the restaurant closed Sunday night, two men wearing ski masks entered, forced the manager to open the safe, then herded the manager and three other restaurant employees into a walk-in freezer, according to police. One of the men then fired a shotgun into the freezer four times, police said, wouding the manager and two of the three other employees.

All three wounded employees remained hospitalized at Alexandria Hospital yesterday.