The Calgary Police Service says it's confident one of its documents, with the names and photos of gang members and found inside a home that was raided last year, was not leaked by its own staff.

Police discovered the two-page document during a raid of a Heritage Pointe home in December that also uncovered a cache of bombs, loaded weapons and illegal weapons, confirmed Staff Sgt. Gord Eiriksson of the organized crime unit on Thursday.

The internal police document — with mug shots from 2005 and names of members who are reportedly part of the FOB Killers gang — was also sent to the Calgary Sun by an unidentified source.

'We're not concerned about any such issues as our department being infiltrated or being compromised — that's not the issue.'

—Staff Sgt. Gord Eiriksson

People arrested in that raid — including Real Christian Honorio who is currently charged with three counts of first-degree murder — are allegedly members of a rival gang.

The document was likely used for identification purposes for frontline officers, said Eiriksson.

"This document was not provided to them by somebody within our service. This document may have been misplaced, may have been taken," he said.

"We're not concerned about any such issues as our department being infiltrated or being compromised — that's not the issue."

When police alerted people listed on the document of what happened, they were met with indifference, said Eiriksson.

"They either brushed it off or weren't concerned by the fact that we had actually found this. Because most of these, the people that are involved in these groups, know each other."

Police bring in more secure measures to store data

An internal probe is underway to find out how the document ended up at the home south of Calgary. Eiriksson suggested it's possible someone stole it, as has happened with documents from a district office before.

"I mean these things happen. It speaks to the sophistication of these organized crime groups. They are utilizing whatever means possible to try to obtain intelligence or information about rival groups and they will look for opportunities to do so."

Former Calgary police officer and gang expert Henry Hollinger said sensitive documents can also end up in the public domain because of the legal process.

"Sensitive police papers that are highly confidential, secret, but in the disclosure package they have to disclose this information to the defence so they can actually mount a proper defence on the charges."

Calgary police have been bringing in more secure measures, such as internal databases, to avoid paper trails, said Eiriksson. The organized crime unit has been using handheld electronic devices, such as Blackberrys, that are encrypted and secure.