Federal investigators have found clues that suggest the robbery of an armored truck last month in New Orleans was an inside job, and the FBI has determined that text messages between the truck’s driver and her partner were deleted, according to authorities.

The Brink’s crew failed to follow company protocol during the heist, according to investigators, and they missed multiple opportunities to avert the Oct. 11 robbery while they were still inside their bullet-proof vehicle.

Police said a pair of masked men robbed the truck a few minutes before noon at the Chase Bank at 1425 N. Broad St.

An FBI spokesman said the robbers fled through a hole they had cut in a wooden fence separating the bank from a neighboring business. Investigators believe the men then ran down an alley before driving away in a GMC Yukon that had been parked on Bayou Road.

The investigation, led by the FBI and the New Orleans Police Department, revealed several irregularities that raised suspicion the robbery was a conspiracy involving the Brink’s crew. Two days after the heist, the FBI searched the driver’s cellphone and “concluded that text messages between the driver and messenger had been deleted,” according to a search warrant obtained by The New Orleans Advocate.

The driver, Sarajevo Smith, became “combative” during an interview with investigators, the document says, and would not allow the authorities to search her cellphone. The FBI also believes Smith researched interviewing techniques used by law enforcement prior to her questioning by authorities.

Investigators obtained a search warrant that said they wanted to scan Smith’s phone for “fruits of the crime (that) may be secreted” there.

Smith, who has not been charged, could not be reached for comment Thursday, and the name of her colleague was not included in court filings.

Brink’s and the FBI did not respond to messages seeking comment.

The reaction of the Brink’s crew also has deepened suspicion. The search warrant alleges that the driver and messenger “had the opportunity to drive off from the (bank) after being ordered inside of the armored car by one of the armed perpetrators.”

“The perpetrator(s) remained outside of the truck and waited for the messenger to provide the money bags from the interior of the vehicle,” the document says.

“Additionally, the driver and messenger did not follow the company protocol, which would have been for the driver to pull off as soon as the perpetrators were observed.”

The authorities also found that protocol had been breached “regarding the double safety feature for opening the side door of the armored car.” A button normally used by the driver to open the side door had been disabled, the search warrant says, and “the driver did not have to press the button in order for the messenger to enter the armored car through the side door. This resulted in the messenger merely unlocking the door himself with a key in order to retrieve the money for the perpetrator(s).”

The FBI’s suspicions added an intriguing chapter to an already rich history of armored car heists in New Orleans, some of which remain unsolved. In February, police booked three men accused of casing and attempting to rob an armored car in Algiers. One of the suspects had worked for the armored car company and was believed to have known the vehicle’s route.

Meanwhile, the FBI is still investigating the carefully orchestrated robbery and fatal shooting of Loomis armored truck driver Hector Trochez in December 2013. Trochez had been delivering cash to the Chase Bank at South Carrollton and South Claiborne avenues when he was gunned down by a masked rifleman.

That heist was reminiscent of a 2007 armored car robbery at a Capital One bank in Riverbend, in which masked men carrying AK-47s exchanged fire with a security guard.

Follow Jim Mustian on Twitter, @JimMustian.