Secaucus was underway long before McGreevey was elected. The credit on that should go to Christie and to Frank Lautenburg for getting the Fed money to do the job.
The NY Times take on the matter is McG had sex with the guy, then appointed him to a $110,000 job during the affair, which lasted several months. The guy demanded $5mn to keep his mouth shut, and McG reported him to the FBI for extortion.
Under NJ laws, state employees have a lot of legal protections against being forced to have sex with the bosses or people in authority. Expect a civil suit on this one...