ST. THOMAS — A third St. Thomas man has been arrested in connection with an armed robbery at Gems and Gold Corner jewelry store, after federal investigators found him with a small arsenal of weapons and a cache of stolen jewelry, according to documents filed in U.S. District Court.

Shemelle Isaac was arrested and charged with accessory after the fact, possession of stolen property, and unlawful possession of firearms and ammunition, according to an affidavit filed last week by an FBI special agent.

Isaac committed those offenses on Dec. 11, the same day another man named Tashawn Warner was arrested in connection with the robbery that occurred three months earlier on Sept. 19, according to the affidavit.

Surveillance video from the jewelry store shows three individuals — a getaway driver and two gunmen, one armed with a machine gun and the other with a handgun — participating in the crime, police said.

A gunman told an employee to open the safe, and then struck him with the gun when the employee said he didn’t know how, leaving a laceration on his head, police said. The suspects smashed the glass cases and made off with thousands of dollars worth of jewelry.

Police tracked the suspects to Bovoni, where two men ditched a getaway vehicle filled with evidence and fled, but the bulk of the stolen jewelry — and the firearms used in the robbery — were not recovered.

Police said they used evidence and an anonymous tip to identify Warner and another man named Jamari Benjamin as the armed robbers. Benjamin was quickly brought in for questioning and arrested about four hours after the robbery, and subsequently charged with two federal crimes, according to court records.

Warner “fits the description of the shorter masked male who is brandishing a rifle type firearm,” while Benjamin fits the description of the taller suspect seen pistol-whipping the store employee, according to the FBI.

Federal authorities executed an arrest warrant for Warner on Friday, Dec. 11 at a home in Estate Langmath, and “immediately prior to his arrest,” he was seen loading bags into the trunk of a gray Toyota Corolla, according to an affidavit filed by an FBI special agent.

A black Infiniti G37x drove up to Warner’s “at a high rate of speed” and stopped, and Warner got out and transferred the bags from his vehicle into the Infiniti, which then drove off, according to the affidavit. Federal agents closed in and placed Warner under arrest, and as he was being taken into custody, “Shemelle Isaac was observed walking from the direction the G37x drove off and holding a child.”

Isaac went into a nearby home and returned without the child and identified himself to the arresting agents as Warner’s friend “Shawn,” according to the affidavit. Investigators located the black Infiniti G37x parked around the corner, and as agents were waiting for a tow truck, Isaac approached and said the vehicle belonged to his girlfriend.

Isaac refused to give agents consent to search the vehicle, and “confirmed he was aware of the article in the paper which was Warner’s arrest warrant for his involvement in the jewelry store robbery and was coming up to speak to Warner about it,” according to the affidavit.

Isaac, court documentes noted, “insisted he needed his daughter’s diaper bag out of the car because it contained her milk, however when agents offered to give him the bag only after they searched it for contraband, he refused.”

At the time of Warner’s arrest, agents said they found $5,520 in the pocket of his pants, and they obtained search warrants for both vehicles.

In the back seat of the Infiniti was a baby’s diaper bag “with a bottle of milk, formula, diapers, bibs, baby shoes and a fully loaded Glock 17 in a holster,” according to the affidavit. “Inside the trunk of the vehicle was a duffel bag containing an unloaded Glock 26, three loaded AK-47 style rifles, four Glock magazines, three AK-47 magazines including a drum magazine, rifle ammunition and a sandwich bag containing 5 gold necklaces and a bracelet.”

The jewelry is consistent with what had been stolen from Gems and Gold Corner, “and one of the rifles resembled the rifle used by one of the robbers,” according to the FBI.

The owner of the store verified that he recognized the stolen pieces, which have a combined estimated price of about $26,000. Agents believe Isaac “was attempting to hide evidence of the robbery from investigative agents and knowingly possessed the firearms in the duffel bag and baby bag,” according to the affidavit.

On Friday, Assistant U.S. Attorney Juan Albino filed a motion to detain Isaac without bond pending trial.

Isaac is facing a long prison sentence if convicted, including a mandatory minimum of 10 years behind bars for the firearm charge, and “it is clear that no condition or combination of conditions will reasonably assure the safety of the community,” Albino argued.

Magistrate Judge Ruth Miller has scheduled a detention hearing for today.

Benjamin was released in October after Miller denied prosecutors’ motion for detention, and a third party posted $10,000 cash and property worth $40,000 as surety for his $50,000 bond. His trial date is currently set for March 1.

Warner was ordered detained without bond Tuesday.

— Contact Suzanne Carlson at 340-714-9122 or email scarlson@dailynews.vi.