"Aggravating circumstances" refers to factors that make a situation worse or more serious. It could be something that intensifies or adds to the negative effects or consequences of an action or event. Full definition
[244] An award of compensatory damages may also include an amount awarded for aggravating circumstances where the defendant's conduct increased the plaintiff's «humiliation or anxiety arising from the libellous statement»: Hill, supra, at para. 188. (courts.gov.bc.ca)
Other states try teenagers as adults only in cases involving extreme violence or other aggravating circumstances. (wxxinews.org)
The other factor, distance and cross border, (three countries: Turkey, the U.S., his home country) further militates against prosecution except for highly aggravating circumstances such as drug dealing, gambling, or sex for pay. (law.stackexchange.com)