From the [1] New York Post:

An ex-con and former upstairs neighbor reportedly was being grilled last night in the savage stabbing deaths of a Jersey City family of four.
Detectives picked up the man, identified by a relative as Edward McDonald, 25, after reviewing surveillance videos from ATMS in Jersey City and Manhattan, WABC-TV and WNBC-TV reported.

The ex-con was providing detailed information about the case but claimed a second man was responsible for the horrific slaying of the devout Coptic Christian family, WABC said.