Five deaths over the last 10 days in the Santa Rosa area may be linked to heroin overdoses, officials said Tuesday.

The Sonoma County Coroner's Office said the final cause of the deaths has yet to be determined, but is warning the public of the disturbing trend.

"The Coroner's Office is concerned that the heroin being distributed in Santa Rosa right now is very volatile and potentially toxic," the Sonoma County Sheriff's Office said in a statement.

Of those who died, the sheriff's office said a 27-year-old woman, a 30-year-old man and a 28-year-old man were transients. The other victims were a 52-year-old man and a 66-year-old woman. All five were found in different parts of the city, according to the sheriff's office.

It's possible that people are mixing the heroin with other things, but that will not be confirmed until toxicology reports are are available, the sheriff's office said.

"All health, rehabilitation and treatment centers need to know that this substance is out there and any signs of overdose should be taken seriously. Anyone exhibiting signs or symptoms of an overdose should seek medical attention immediately or call 911," the sheriff's statement continued.

No other information was immediately available.

Editor's note: The sheriff's office initially reported nine deaths and then updated that number.