wish I could be more certain and more concrete in what I say, but there are challenges in these cases,  he continued.

What you can do:

If you have information that could help in the investigation, the police have established a tip line - (517) 483-6023.

One suspect in custody

Dig deeper:

Backus reiterated that one case was different from the others, in that the victim was stabbed and a person was in custody.

 The question that's been posed to us, is, is this the suspect for all the instances? I want to be very clear - that is a challenging question to answer and one that I have to be very cautious on,  Backus said.

Defining  serial killer 

FOX 2 spoke with a criminologist about what an investigation into a possible serial killer involves.

What they're saying:

 The phrasing in and of itself is part of a definition, certain types of homicides that the FBI has put together. So, technically a serial killer (is) someone who has killed multiple people, you have to have killed at least three people with a  cooling off  period in between each of those. The cooling off period, of course, will vary by offender,  explained Dr. David Hayes.

 (This differentiates from a mass murderer, who kills three people all in one concentrated location, or a spree killer who kills three or more people in a succession of different locations,  Hayes continued.

Dig deeper:

As for this particular investigation that's playing out in Lansing, Hayes said investigators will be looking for connections between the cases, which he says could be difficult in this situation.

 An unhoused individual, a homeless person, they don't have that digital footprint - or even that physical footprint - that we have, where people know where we're at, people know what we're doing; we see other people every day. And the people that are living alongside an unhoused person or in the general area are going to be pretty reluctant to talk,  Hayes said.  So we don't really have that connective tissue that could really pull these together; that's going to make this investigation far more difficult. 

He added,  If this does turn out to be a series of connected deaths, then we're looking at someone preying on incredibly vulnerable people.