Three days after nearly $5 million in gold was stolen from a truck along I-95 in North Carolina, authorities suspect the truck was either targeted ahead of time by thieves or it was an inside job, although the two guards involved are not currently suspects.

The truck pulled off the highway in eastern North Carolina about 6:30 p.m. Original reports cited mechanical problems, but now the Associated Press is reporting that the truck pulled over because the truck's passenger felt sick and said he smelled fuel fumes.

The drivers/guards for Transvalue Inc. of Miami told police that immediately after they pulled over, a white van pulled up and three armed men tied their hands behind their backs and made them walk into the woods, while they cut a padlock off the trailer and took out five buckets holding 275 pounds of gold bars worth about $4.8 million.

"There's a possibility that they could have been doing some type of surveillance" of the tractor-trailer and its route, Wilson County Sheriff Calvin Woodard Jr. said during a news conference, reports Reuters.

Not mentioned in published reports is the fact that Miami, where the load originated, is one of the nation's hotbeds for cargo theft by organized cargo theft rings. A common tactic for these professional cargo thieves is to stake out companies that haul valuable cargo. Thieves could have been following the rig for some time waiting for an opportunity. 

A search warrant seeking permission to search the cellphone of the truck's passenger says "there is suspicion at this time that this could be an inside job due to the circumstances of the robbery."

However, published reports also note that there was a language barrier hampering investigators.

Some of the things that seem odd about the incident, according to published reports:

• The fact that the truck was robbed immediately after pulling over at an unannounced stop, since the truck had no external markings indicating the cargo.

• The guards got out of the tractor-trailer without their guns, a company security violation

• No security measures other than a padlock.

Transvalue is offering a $50,000 reward for information leading to an arrest or recovery of the stolen property.