Here are the reasons I believe JB maybe responsible for Manorville (and then via JT and MB..to GB4 and in turn to AC4)
Proximity to the crime scenes/he has lived in Mastic, Shirley & Manorville.
He worked as a construction sub-contractor in the area of Wading River RD.
His business address, in Manorville, is his home address.
He has the tools to cut someone up.
If he killed RT then there is a definite link to MB through Rita's daughter.
Melissa disappeared off the curb in the Bronx. Both of his parents are from the Bronx.
We know he has a previous DUI or DWI. So, he has been a drunk white guy. And he is from NY so to Amanda he may not have sounded like he had an accent different from her own. To a late teen, a 41 year old would sound like an older guy.
He has family in West Babylon, Central Islip and possibly Long Beach.
He has gone to great lengths to keep his name off the paperwork on "his business." And, there is VERY little in the way of any business reviews, memberships, certifications, etc You name it, there is little to nothing to be found on him. The business went under in 2006. WHY that year? (2006 was the year AC4 were murdered and one year before the GB4 started turning up missing.) Perhaps he is able to get referrals through his brother's painting company and other friends and family. Being a sub contractor with little to no internet publicity makes me wonder how he could afford so much land and such a nice home.
He comes from the same town as Kim Raffo. Just a mile and a half apart. (She spent three weeks on LI in the autumn of 2006 where it has been reported that she and her ex husband worked on a friend's construction job/jobs.)
His phone number and family members (through their facebook affiliations) are directly tied to religious outreach.
Well, that is all I can think of right now.