Petaluma police were investigating the discovery of a man's body under the D Street bridge Wednesday afternoon, the third such find within a month.
Lt. Tim Lyons said the death, reported about 3:50 p.m., may have been a suicide.
He said it appeared the man may have been a transient. Detectives were conducting a search in the area for further clues to the man's identity.
The Sonoma County coroner will conduct an autopsy to try to identify the man and determine a cause of death.
The area is frequented by transients, Lyons said. Several years ago, a fence was placed under the bridge to prevent loitering.
Police were also waiting to identify the remains of a man found in a Petaluma creek bed last week, whom they also believe was a transient.
The man, believed to have been dead for several days, was found near several homeless camps in Willow Brook Creek on the north end of town, not far from Redwood Highway east of North McDowell Boulevard.
He was found by a dog walker.
On Aug. 16, a woman's skeleton was found in an undeveloped area of the McNear Peninsula near downtown. Police believe she also may have been a transient, Lyons said, and her identity also hasn't been confirmed.
Anyone with information about any of the cases is asked to call 778-4372, the anonymous tip line at 781-1200 or email firstname.lastname@example.org.