Kim K’s terrifying ordeal inside a Paris apartment earlier this month lasted for almost an hour. Picture: Chris Pizzello/Invision/AP, File

A Paris judicial police source tells US Weekly that the gang of robbers stayed put in and around Kim’s apartment for up to 49 minutes, which is in contrast to earlier reports that stated the men were in and out in a matter of minutes.

Police leave Kim’s apartment on the morning after the heist. Picture: AFPSource:AFP

“They acted like they had all the time in the world,” the police insider told US Weekly. “It is quite incredible that they managed to hang about for so long without anyone calling us.”

It is understood authorities used footage from a traffic camera to determine how long the gang had been at Kardashian’s private residence in the Hôtel de Pourtalès.

With mounting speculation since the robbery occurred that it was an inside job, the source makes another startling claim: the robbers were able to let themselves in.

The first three suspects arrived on bicycles clad in black jackets at 2:18am.

“They clearly knew the security code of the main doors, and let themselves in without any problem at all.”

Kardashian has kept an uncharacteristically low profile since the terrifying ordeal.Source:Splash News Australia

The remaining two men arrived on foot fourteen minutes later and used the same entrance to gain access to the building.

DNA traces have been found inside the apartment Kardashian was staying in, a source told AFP last week.

It comes as French prosecutors formally opened an investigation into the robbery in which the US reality TV star lost millions in jewellery.

The investigation is focusing on “armed theft in a gang, criminal conspiracy and kidnapping,” another source said.

The men who burst into the residence in the early hours of October 3 tied up Kardashian and stole jewellery worth around $14 million.