A car found engulfed in flames on Dial Close, Sheffield Lane Top, Sheffield, had been set alight in an arson attack.
The Citroen Saxo was found burning at 10pm on Monday.
And at 6.30pm the same night a Ford Ka was set on fire on Rhodes Street, Park Hill, Sheffield.
Firefighters tackled both blazes.
n Anyone with information should call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.