RCMP officers who specialize in matters of national security have joined the investigation into an alleged bomb-making scheme which police say involved four people with ties to Western University.

The RCMP’s Integrated National Security Enforcement Team (INSET) is providing “investigative support and assistance” to the police in London, Ont., a Mountie spokesperson said in a statement, while offering few specifics.

Three men and one woman — all current or past Western students — face a slew of charges alleging, among other things, that they were storing chemicals that could be made into explosives at a house just west of campus and had manufactured a gun.

The charges came after a trepassing investigation on campus led police to 212 Chesham Pl., where, they said last week, the chemicals were found.

It’s unclear why the INSET is involved and one counterterrorism expert says it’s too early to speculate about what the accused were doing.

Phil Gurski, a former Canadian Security Intelligence Service (CSIS) analyst, says some aspects of the case suggest espionage.

WATCH | Charges laid in London:

4 people charged in London, Ont., bomb-making scheme

Three men and one woman with ties to Western University face charges alleging that they were storing chemicals that could be made into explosives at a house just west of campus in London, Ont.

But others don’t align with what he saw during his three decades working in intelligence.

People accused of making bombs for terrorist or “transnational” purposes typically have a clear motive, he says, and the accused in this case are much younger — all in their 20s — and less experienced than he would expect of spies.

“We need a lot more information … before we can come up with any even remotely tentative conclusions,” Gurski, who is now CEO of Borealis Threat and Risk Consulting, told CBC News.

“At this juncture, there doesn’t seem to be a violent motive behind this. The explosives are serious, the firearm is serious, but what they were seeking to do with that weaponry … is completely unclear.”

The firearm which was allegedly manufactured is a seemingly unique aspect of the case, because it does not appear to involve organized crime, according to Francis Langlois, a professor at the University of Quebec in Montreal, who studies legal and cultural firearm issues.

Even so, such guns are becoming more and more common.

“They are more and more easy to make, plans are available on the internet and the machines used to print them are also easier to get,” said Langlois.

All four of the accused remain in police custody.