The phrase in regard of was formerly used as equivalent in meaning to
on account of, but in modern usage is often improperly substituted for
in respect to, or in regard to. G. P. Marsh.
Change was thought necessary in regard of the injury the church did
receive by a number of things then in use.
Hooker.
In regard of its security, it had a great advantage over the
bandboxes.
Dickens.