RALEIGH, N.C. (AP) — Shortly after dusk along a lonely stretch of Interstate 95, armed robbers hijacked an armored truck, tied up the two guards and disappeared into the night with 275 pounds of gold bars. 
 
 The guards working for Transvalue Inc. of Miami reported pulling off to the side of the interstate about 6:30 p.m. Sunday after their vehicle began having mechanical problems in eastern North Carolina, according to the Wilson County Sheriff's Office. 
 
 The guards told police they were surprised by three armed men driving a white van who ordered the guards to lie on the ground, tied their hands behind their backs and then marched them into nearby woods. 
 
 The robbers then helped themselves to barrels filled with about $4.8 million in gold before making their getaway. Transvalue said its employees were not injured during the heist. 
 
 Transvalue chief executive officer Jay Rodriguez said the truck carrying the gold bars left Miami about 4 a.m. Sunday. The load was headed to Attleboro, Massachusetts, a town south of Boston nicknamed "Jewelry City" for the large number of manufacturers based there. 
 
 "At this time we are working with the authorities to try and resolve this matter," Rodrigez said. "We are offering a $50,000 reward for any information leading to the arrest of these criminals." 
 
 Though Interstate 95 is one of the busiest roads on the East Coast, the rural stretch where the robbery occurred is relatively isolated, bordered by trees and farms. 
 
 Wilson County Sheriff Calvin Woodard Jr. declined interview requests Monday and did not respond to messages from The Associated Press seeking additional information, such as what weapons the robbers used or how they managed to get the armored truck open. No detailed description of the suspects or their vehicle was released. 
 
 Shelley Lynch, spokeswoman for the Federal Bureau of Investigation's Charlotte field office, said agents are assisting the local sheriff and are working to determine whether a federal crime has been committed. 
 
 According to its website, Transvalue specializes in transporting cash, precious metals, gems and jewelry in armored trucks. The company says its shipments are insured for up to $100 million. 
 
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 Follow Biesecker at http://twitter.com/mbieseck ||||| Police suspect that the alleged armed robbery of a truck transporting bars of gold in North Carolina was an inside job as more details about the highway heist have emerged, according to search warrant application that was obtained by ABC News. 
 
 Three suspects allegedly stole $4.8 million-worth of gold after one of the two armed guards -- the driver and another man, both inside the truck's cabin -- said that he felt sick and prompted the driver to pull over, Wilson County Sheriff Calvin Woodard Jr. told reporters today. 
 
 That account is different from what was presented in the first police report on the case, which said that a mechanical issue caused the truck's driver to pull over. 
 
 “There is suspicion at this time that this could be an inside job due to the circumstances of the robbery," a Wilson County Sheriff’s Office detective wrote in a search warrant application to get access to one of the guards' cell phones, one of two search warrants in the case obtained today. 
 
 "The fact that the truck was robbed immediately upon it pulling over at an unannounced stop is suspicious in and of itself," the document added. "It is also suspicious because there are no markings on the side of the truck that would indicate the type of cargo contained therein. The suspects also went directly to the trailer and found the gold which was in unmarked five gallon buckets. It is not believed that this is a random act due to the nature and facts of this robbery." 
 
 The second search warrant application was to get access to the truck and the trailer it was pulling. 
 
 Woodard told reporters today that the case was "suspicious," but declined to reiterate the theory expressed in the search warrant that the robbery could have been an inside job. 
 
 WTVD 
 
 Woodard shared sketches of the three suspects who allegedly bound the hands of the driver and the passenger, and a photo of a traffic cone that was placed behind the truck as the suspects allegedly removed the gold from the vehicle after breaking a lock on the back. The traffic cone had the marking of a company that only does work in Florida. 
 
 WTVD 
 
 The truck was bringing gold and silver to Bridgewater, Massachusetts, and being driven on I-95 by armed guards employed by a Miami-based company, TransValue Inc., Woodard said. 
 
 One of the search warrants states that approximately $5 million-worth of silver was left in the truck, meaning that when the truck left Miami on Sunday morning, it had close to $10 million in metals inside the back compartment, which, the sheriff said, was protected solely by a Master lock on the door. 
 
 "The suspects attempted to steal the truck and trailer but could not get the truck started," according to one of the search warrants. "The truck was in proper working condition so the suspects had to [have] not been experienced in the operation of a commercial motor vehicle. The suspects loaded the gold in the minivan and fled the scene." 
 
 WTVD 
 
 The metal was owned by Republic Metals Corporation in Opalocka, Florida, according to a search warrant. The company did not immediately respond to a call seeking comment. 
 
 The police said they were seeking a search warrant for the phones of the armed guard who felt sick because of the suspicious nature of the case, but Woodard said at today's news conference that the driver and the passenger have not been considered suspects. Both men have been interviewed separately several times by police, Woodard added. 
 
 Woodard noted that the driver and the passenger apparently violated their company’s policies by exiting the vehicle without their firearms and leaving the firearms inside the truck.
– Highway robbery in North Carolina: Police and the FBI are probing a heist on Interstate 95 Sunday night in which around $4 million in gold was allegedly stolen from a truck. Two armed security guards who were transporting the gold from Miami to Massachusetts say that after they pulled over at mile 114 when the truck had mechanical problems, they were approached by three armed men in a van who tied their hands behind their backs and ordered them to walk into the woods, WRAL reports. While the TransValue guards were in the woods, the bandits made off with 275 pounds of gold bars, according to the Wilson Times. Interstate 95 is a busy road, but the heist took place along a lonely, isolated stretch of it surrounded by woods and farms, reports the AP, which notes that it isn't clear how the robbers were able to get the truck open. TransValue, which is based in Miami, says its guards were not injured in the heist and is offering a $50,000 reward for information leading to the arrest of the robbers. The FBI is investigating to determine whether a federal crime occurred, WRAL reports. (In another gold heist earlier this year, thieves made off with gold nuggets from the Wells Fargo History Museum.)