I don't think they have a suspect. Just a basic description. They aren't gonna taunt or infer "we are coming for you!", they would just make an arrest and then tell the public why.
I think they have a strong suspect in mind. The actual quote was close to that they were getting a better physical description of the suspect. I believe they are calculating every possible measurement of the suspect of their physical size, such as height, shoulder width, calf width. Then they will see if their prime suspect fits all these attributes. I am sure they have other digital information about their suspect also. Maybe texts from their phone, possible car sighting going to and from the church, anything to hopefully discredit the alibi or other lies of their suspect. I do believe they are really close. They are leaking out some information just to tighten the "noose" around their suspect and make them misstep.
But then again, most of this hope in we getting the real killer soon.