The Independent Office for Police Conduct says the 94-year-old was hit on Merthyr Road in Cardiff.
Simon Haydock spent the bulk of his mother's £137,000 in the space of a month, a court hears.
The 65-year-old woman died in hospital following a collision with a white van, police say.
Newport boss Mike Flynn is leaving nothing to chance ahead of the FA Cup second-round replay against Wrexham, even cancelling the Christmas party.
Ospreys will be without injured Wales prop Nicky Smith for Friday's return European Challenge Cup pool game against Stade Francais in Paris.
South Wales Argus
About these results
Good Evening Wales
The new family drama starring Sheridan Smith
Sign up for our newsletter