OAKLAND (CBS SF) — Three suspects have been arrested in a brazen daylight robbery of an armored Loomis truck delivering cash to an Oakland Wells Fargo branch last June that authorities are calling an inside job.

Oakland police said a lengthy three-month investigation has resulted in the arrests of 35-year-old Duane Jackson, his 23-year-old nephew Damien Jackson and 25-year-old Mercadiez Moore.

(L-R) Duane Jackson, Damien Jackson, Mercadiez Moore (Alameda County Sheriff’s Office)

According to court records, Damien Jackson was the guard driving the armored vehicle on the day of the robbery and has admitted his involvement.

Duane Jackson and Damian Jackson were being held on second-degree robbery and other felony charges. Moore, who authorities characterize as Damien Jackson’s girlfriend, has been charged with receiving stolen property and third-degree firearm storage.

On June 27 at 10:51 a.m., Oakland police officers responded to an armed robbery report of an armored Loomis truck in front of the 10700 MacArthur Blvd. Wells Fargo Bank location.

The custodian of the armored truck was delivering currency to the bank when two suspects, armed with assault weapons, approached him and demanded the cash. The suspects then fled the scene with more than $100,000 in cash in a red Honda Civic.

Oakland police Lt. Steven Nowak lead an extensive three-month investigation that eventually identified several individuals connected with the robbery.

“(Officer Michael Khem and Officer Jorge Garcia) worked tirelessly with specialized units in identifying the responsible persons in this crime which resulted in key arrests, confessions and a cache of illegal firearms,” Nowak said in a prepared release.

“You see it in the movies, I just didn’t think that still happened. I was little bit surprised it was an inside job and family affair,” said OPD officer Jorge Garcia.

Officer Mike Khem said that OPD was initially suspicious of the family connection because the armored truck company said a majority of similar heists are inside jobs.

“The driver was definitely involved–he helped set up the actual heist and the robbery took place and for several months. They probably thought they got away with it,” said Nowak.

A display of firearms recovered in the investigation into an armored car robbery. (Oakland Police Dept.)

Nine search warrants were served leading to the arrest of the Jacksons and Moore and the seizure of 11 firearms including handguns, shotguns, rifles and assault rifles.

Authorities said some of the stolen money was used to buy vehicles and a motorcycle.

As the investigation continues, investigators ask anyone with information to contact the Oakland Police Department’s Robbery Unit at (510) 238-3326.

KPIX 5’s Andria Borba contributed to this report.