Eric Amaral, who was arrested Tuesday evening after allegedly shooting a Waterloo Regional Police officer with a pellet gun, has been identified as a person of interest in the homicide of Michael Gibbon.

He’s far from the only one.

Police said Thursday that they’ve identified 30 persons of interest in connection with the death of Gibbon, who was found last week with a fatal arrow wound in his chest.

No arrests have been made in the case.

Thursday, police returned to Breithaupt Park – near where Gibbon was found. Officers were spotted taking photographs and placing evidence markers.

Police say they’re looking to identify and speak with each of their persons of interest, in the hope it will help them narrow down their list and figure out what happened to Gibbon.

They did not say if Amaral remains a person of interest.

One known person of interest is an olive-skinned man who may be in his 40s.

A computer-generated image of his likeness was released days after Gibbon’s death.

Police said at the time that the man was not considered a suspect, but may have been in the area around the time of Gibbon’s death.

So what defines somebody as a person of interest?

Chris Lewis is a former commissioner of the Ontario Provincial Police and CTV’s public safety analyst.

He says person of interest is a relatively new and “fairly loose” term that describes a wide range of people.

“A person of interest is someone that has, somehow or other, come to the interest of the police,” he said.

“Maybe it just matches the description they have. Maybe he drives a vehicle similar to a vehicle they’re looking for.”

Once a person of interest has been identified, Lewis said, investigators will look to locate them and ask questions about where they were at the time the crime being probed took place, and whether they know the victim.

Detectives will then follow up on that information, in order to verify it.

“Really they’re just trying to narrow it down,” he said.

Kitchener-based criminal lawyer Darwin Witmer says anyone told they are a person of interest should speak with a lawyer before talking to police.

“Your case will be different from anyone else’s, so in confidence you can talk to a lawyer about what issues you have and what proper legal advice you could get,” he said in an interview.