A grieving Regina father says his family is strong and coping as best they can following the deaths of two siblings due to overdoses linked to the drug fentanyl.

Alex Hamilton learned from police about the deaths of his adult children, Niki who was 33 and Josh, 36, and how the initial investigation suggests a lethal dose of fentanyl was suspected.

'I don't know why she did it.' - Alex Hamilton

"The loss of two children, directly related to drugs... it's hard. But we've got a strong family," Hamilton said Friday.

Hamilton said family and friends are preoccupied with good memories about the sister and brother but the role of drugs in their lives is in the foreground.

"I knew about their drug addiction for a while," he said. "I'm a former addict myself."

alex hamilton

Alex Hamilton's adult children, a daughter and a son, died of overdoses. (CBC)

He said he was able to overcome an addiction to heroin, which started when he was 15, and thought his children — seeing first-hand the challenges of getting clean — would benefit from that knowledge.

"My daughter ... she was in the process of straightening out her life," Hamilton said. "Maybe [she] figured one more party or one more shot. I don't know. I don't know why she did it."

He said he thinks his son may have been feeling low about the death of his sister and turned to drugs.

"My son, still an addict obviously, probably figured [drugs] would take some hurt away," he said.

Hamilton said the issue of how to deal with drug addictions needs to be addressed in comprehensive way, through the health system and other measures, not just as a criminal matter.

Warning to users

He also had a strong message for people involved in drugs, or tempted to try out a new drug, when it comes to what is out on the streets.

"You think your friend's a friend and he's putting something in your arm, or giving you something to make you happy. Be very leery. Be very leery," Hamilton said. "People aren't your friends. You're nothing but a piece of meat to make them money. That's what the game's all about. I know it well."

Police in Regina have noted that fentanyl can be 100 times more potent than heroin and people don't know if it's been added to what they're already hooked on. According to officials, fentanyl led to 22 overdose deaths in Saskatchewan in 2015.

Memorial gatherings and a funeral are set for Josh Hamilton on Sunday and Monday. They're cremating Josh in the same suit he wore to be a pallbearer at Niki's funeral, just days before his death.

According to online remembrance pages, Niki had three children. Josh was the father of one boy.

With files from CBC's Tory Gillis