Depending on the stability of company contracts, construction workers don't always stay continually with one company as onsite jobs come and go. They could just show up on a jobsite, talk to a foreman and start working once the proper paperwork is in for payroll and workers comp. Some small companies pay their workers under the table tho. That's a person who might not go to LE if DN or BG had been working for them. There could be a long string of paying under the table so as not to pay employer taxes, workers comp, etc. That owner might choose to not talk. But that would only be with a small company. A bigger one couldn't and wouldn't. So, it's important to find out who his friend says they worked for and see where their jobs were at the time of the murders