BANGOR – Investigators may be close to identifying the man whose burning body was discovered under a bridge Tuesday, but a determination of what caused his death may take longer, authorities said Wednesday.

The state medical examiner’s office performed an autopsy on the body in Augusta Wednesday, but further study and testing are needed to determine the cause of death, which is being considered suspicious, according to an investigator.

As for who the man was, Bangor police Detective Lt. Tim Reid said a positive identification could come in the next day or two.

“We have leads we are working on,” he said at the Bangor Police Station.

Because there are gaps to fill in, Reid said the incident is being classified as suspicious until determined otherwise.

“Until we get some answers, we have to classify it as suspicious,” Reid said.

Investigators returned Wednesday to the Harlow Street bridge over the Kenduskeag Stream between Mill and Nelson streets. The body had been found burning about 5:45 p.m. Tuesday, a busy time for traffic. A passerby saw smoke and reported the fire.

The body was burning when firefighters arrived, but it wasn’t clear if the man was still alive at the time. Reid wouldn’t comment on when the man was pronounced dead or whether efforts to resuscitate him were made.

“I’m not going to go there,” Reid said by telephone Wednesday afternoon.

Tuesday night, the investigation extended from the bridge to Harlow Street where police officers walked toward the Penquis CAP building near the Margaret Chase Smith Federal building, scanning the road with flashlights.

Wednesday there was little sign of the activity of the night before.

Large rocks line the steep bank of the stream in the vicinity. An opening in the rocks revealed blackened ground, perhaps from a fire.

Underneath the bridge past a low green steel beam, lay T-shirts, coats, gloves and other clothing. Farther down, a toothbrush rested on a stone near a shirt and a brown leather winter boot. Another boot lay on a shelf where the bridge’s cement supports meet its metal supports.

Although there is no proof the man was homeless, the discovery of the burning body comes at a time when violence against homeless people is attracting increased attention.

On Sunday, a homeless man sleeping in a park in Boston was assaulted and then set on fire. His assailants drenched him with a flammable liquid and set his legs on fire. Attacks elsewhere and in Maine have caught the attention of state lawmakers who on Wednesday began considering a bill to increase protections for homeless people in Maine.

Although investigators have yet to determine whether the man died at someone else’s hands or to confirm that he was homeless, one local shelter director said violence against the homeless is common and increasing.

“Why are we surprised?” Stephen James, director of the 47-bed Acadia Recovery Community in Bangor asked Wednesday.

Homeless people are derided and isolated. Verbal assaults have turned physical, James said.

“These people are marginalized and marginalized people experience violence all of the time,” he said.