The deaths of seven people in the past six months in the Petaluma River and along the city's byways are disturbing but not a sign of increasing violence or criminal activity, police and homeless advocates say.
All the bodies have been found outdoors. One was the skeletal remains of a woman on the McNear Peninsula. Two others were suicides. Four had been homeless or were homeless at the time of their deaths.
Foul play isn't suspected in any of the cases, police said.
If anything, a theme may be hopelessness, said Mike Johnson, the head of Petaluma's Committee on the Shelterless.
"It continues to raise a flag," he said. "They were all extremely vulnerable individuals."
That vulnerability has many causes.
"The kinds of things that make people vulnerable are the kinds of things that are killing these folks: a history of drug use, alcohol use, what kind of condition their bodies are in ... co-occurring health problems — diabetes on top of liver disease on top of heart disease. They all stack up."
The suicides also are a form of vulnerability, he said: "They've got some serious, maybe untreated, mental health issues they're struggling with."
Police say the frequency of the deaths is unusual.
"I don't think we've had this many found outside in the elements before," Lt. Tim Lyons said. "It's different than in the past, when we've had one or two a year."
Still, there doesn't seem to be many common threads linking the most recent deaths.
None occurred during the coldest part of winter and they were spread throughout the city. Some of the causes of death were undetermined, pending toxicology reports.
Johnson said there are about 30 homeless deaths a year in Sonoma County. Santa Rosa and Sonoma County law enforcement representatives said they haven't noticed more deaths in their jurisdictions.
If Petaluma has had more than usual, it may be a reflection of additional homeless living in the area. Over the past two years, Petaluma experienced the largest increase in homelessness in the county, more than double, from 465 to 909, according to the homeless counts conducted in 2011 and 2013.
At the time Petaluma's homeless population rose by 444, Rohnert Park's numbers fell 400.
That may be a result of increased law enforcement interactions, the good reputation of the services provided by COTS or other reasons, Lyons and Johnson said.
Visibility of Petaluma's homeless encampments also has increased as Highway 101 and SMART train construction has displaced traditional camps along the tracks or under overpasses.
"Over the last year, we've definitely seen an increase in the amount of camps and trash," Lyons said. "It goes along that people are going to pass away because they're not always in the best health, are exposed to elements, or don't have — or choose not to get — health care."
Police are planning a citywide cleanup of homeless camps next month during which they will notify trespassers that they need to vacate. A few days later, cleanup crews — including those from COTS — will clear out the abandoned belongings.