TRENTON, N.J. — A former aide to Gov. Chris Christie whose job included getting endorsements from mayors, one of whom was apparently targeted in the political payback plot orchestrated by Christie loyalists, was to appear Tuesday before lawmakers investigating the scandal that’s engulfed the governor’s administration.

The former aide, Matt Mowers, is the fifth person subpoenaed to testify before the Democrat-led panel. He worked in Christie’s office and on last year’s re-election campaign and is now the executive director of New Hampshire’s Republican Party.