Five people in Calgary have been charged in connection with an investigation into ecstasy laced with the deadly drug PMMA, CTV Calgary has learned.

Arrests made in February led police to a stash of pills, which were revealed to contain the additive after lab testing. In some cases, the suspects in the PMMA case were first brought in on other charges, including two people arrested after being chased down by Mount Royal University security.

Police say they will make a major announcement with more details on the arrests in the coming days. Several recent deaths in Calgary and Vancouver have been linked to ecstasy pills laced with the drug.

PMMA, or para-Methoxymethamphetamine, is a psychedelic drug and stimulant. It can cause the body to heat up to the point of severe brain and organ damage or death. It appears to make ecstasy take longer to take effect, which can prompt users to take more pills, resulting in an overdose.

Carol Dahl, whose son Daniel died after taking the drug in December, says she's relieved to know some sellers may be off the street.

"I was absolutely amazed," said Dahl, who believes she knows who sold the drug to her son. "For the longest time, I didn't have any belief the police were going to catch these guys."

Dahl said she will be watching closely to see if the man she suspects is among those arrested.

But while they may mark some progress, the arrests don't mean all pills containing PMMA are off the streets, says Calgary police Sgt. Mike Bossley.

"It is a cash business, so we don't know if some of the dealers are just sitting on some of the drugs right now and not moving them because of the concerns that have been raised," said Bossley. "We don't have anything to suggest they're pulling the drugs off the street at this point."

Local police are warning young people to stay away from all ecstasy, since it's virtually impossible to tell what has gone into it.

It's not known whether the drug's makers added PMMA intentionally or by accident during the manufacturing process.

B.C.'s chief coroner, Lisa Lapointe, said in January that her office had never dealt with deaths caused by the drug before the recent incidents. She said the coroner's office did not begin testing for PMMA until it was linked to the Calgary deaths.

In most of the five B.C. cases where people who took the laced pills died, they had taken other drugs as well as alcohol. But in one of the five deaths, the individual took only one tablet, prompting Lapointe to point out: "There is no known safe dose."

The coroner's service has emphasized it has no idea how much ecstasy currently in circulation contains the chemical. The Canadian Press reported that B.C. police have noted unique markings on ecstasy pills suspected to contain the lethal additive, but are reluctant to reveal the markings to the public because they don't want users thinking other ecstasy pills are safe.

With files from CTV Calgary's Bridget Brown